Kam Lau (BS '78, PhD '81) , Electrical Engineer and Laser Dynamicist

Whether through high speed wires or in wireless communications, so much of our internet-connected world rests on the electrical engineering innovations of Kam Lau. His achievements in laser dynamics and radio-over-fiber technology have been applied to profound effect in applications as wide-ranging as interplanetary exploration, radio astronomy, particle physics, and nuclear testing. In the discussion below, Lau emphasizes the importance in engineering of always keeping end uses top of mind; at the same time, he expresses amazement in some of the ways his work has been adopted in ways for which he could not imagine.

Raised in Hong Kong, Lau distinguished himself through the arts during his teens, and his ink paintings have been featured in galleries and museums around the world; six of his paintings are currently in the collections of two museums. Coming to Caltech in the 1970s, Lau quickly appreciated all of the exciting possibilities in lasers and fiber optics, and he chose to stay at Caltech for graduate school to join the research group of Amnon Yariv. Upon graduating, Lau became one of the founding members of ORTEL, a company that found a niche making high speed semiconductor lasers capable of reproducing high-quality signals into homes and businesses through cable wires. The company revolutionized the capabilities of home cable and internet.

After a brief appointment at Columbia University, Lau joined the Electrical Engineering faculty at UC Berkeley in 1990, where he continued his laser work, both for applications and for fundamental research. A brain surgical mishap in the early 2000s, which he discusses poignantly, cut short his research career, and he decided to go emeritus in 2005. Despite not being able to remain active in research, Lau stays up to date with the literature, and he continues to feel pride in seeing the many applications of his work, from neighborhoods to across the solar system. For his achievements, Lau is a recipient of Caltech's Distinguished Alumni Award of 2022.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Monday, January 2nd, 2023. It is my great pleasure to be here with Professor Kam-Yin Lau. Kam, it's wonderful to be with you. Thank you so much for joining me today.

KAM-YIN LAU: Certainly.

ZIERLER: To start, would you please tell me your current title and institutional affiliation?

LAU: My current title is Professor Emeritus of Electric Engineering and Computer Science at UC Berkeley.

ZIERLER: When did you go emeritus?

LAU: In 2005.

ZIERLER: Have you remained active in the field? Do you continue to do research?

LAU: Well, really not much research since then. I still keep up with the literature, but to do active research, first of all, you have to interact with people on a day-to-day basis, ideas back and forth. It's harder to do research by just—unless you are a theoretician, then you can just sit in a room and work by yourself. But in an applied field like this, I find it hard to actually do something that is current and meaningful. So, I really haven't done much frontier stuff lately, even though I have tried to keep up with what is happening.

ZIERLER: What kinds of things are you interested in? What have you been up to since 2005?

LAU: It's pretty much still, in general, on high-speed photonics, microwave photonics, and also in what they call nanophotonics these days, and silicon photonics. Along those areas are really what I still quite actively keep an eye on.

ZIERLER: What would you consider your home discipline? Are you an electrical engineer, applied physicist? What's the best term for you?

LAU: I would still classify myself as an electrical engineer, even though the definition of electrical engineering has evolved quite a bit over the last few decades. They now incorporate really a whole bunch of what was traditionally physics and applied physics stuff. That wasn't recent, because even back towards—like my Caltech undergraduate advisor, John Pierce, he made his mark in traveling wave tubes, and that is very physics-y stuff, really, electrons and interaction with the circuits. So, I think the whole field of electrical engineering is really, really broad right now. Of course now it broadens out to artificial intelligence and machine learning, and all of those are considered electrical engineering.

ZIERLER: In thinking about your research motivations, are you always interested in applications, or are there aspects of your research that were more fundamental?

LAU: I would say that my work has always been applications-driven. I kind of identify an application area first, and then I delve into it. If that requires some theoretical undertaking, then that comes along, but the motivation has always been application.

Electrical Engineering for Space

ZIERLER: In looking at all of your contributions well outside the traditional boundaries of electrical engineering—your work in space physics, for example—what's the big story there? What's the lesson in terms of the things that you've worked on and how widely they've been applied?

LAU: The application of RF over fiber in space exploration is what I think as really quite impactful. It basically is concerned with the ultra-precise transfer of time and frequency over long distances. That's really what is fundamentally about. To navigate and find out exactly where the spacecraft is, millions of miles away, you really have to—in a sense, you do a triangulation, to find out where the spacecraft is. Of course, it's triangulation on the scale of millions of miles, and you better be ultra-precise in measuring your angles and measuring your time. That basic work of ultra-precise transfer of time and frequency really applies to—at least my work started with the Deep Space Network, and then that basic concept and system now is applied to all radio telescopes, and also in high energy accelerators. Because in accelerators, you have to do a very precise timing measurement between the time you shoot a particle out and the time when they actually collide with something in the collision chamber many miles away. You need to measure it on the accuracy of a picosecond timescale. So they all need that fundamental technology, how they measure time, how they transfer time over long distances. That's fundamentally what it's about.

ZIERLER: A hallmark of your career has been blending academic work with business ventures, with entrepreneurial pursuits. What are some of the lessons? What are some of the benefits of having a foot in both worlds?

LAU: First of all, I have come to the conclusion that you can do an invention, and you can do an advancement, but you really don't have the kind of impact unless you put something in the hands of the broad user so other people can also use the same tools to further the invention. That's where the impact comes. Otherwise, the impact will be limited, if other people don't have access to the same thing that you have, to make further advancement. So I think that the commercialization—well, you can say commercialization, but basically making something that is really broadly available to a lot of people—is an important part of expanding the impact of someone's work.

ZIERLER: The reason we're together today, of course, is that you were recently named the recipient of the Distinguished Alumnus Award at Caltech. First, congratulations on that.

LAU: Thank you very much.

ZIERLER: What was that like, when you received the news, and what opportunity did that give you to reflect on what Caltech made possible for you?

LAU: First of all, I was of course extremely ecstatic when I heard the news. Then I looked at the list of former recipients [laughs] and I thought, "Why should I qualify?" Because if you look at the previous list of recipients, of course you have Nobel laureates, like Charles Townes and Kip Thorne. Then you have industry pioneers—Gordon Moore, Simon Ramo. Then of course you also have the directors, all those big national lab directors. There were two DARPA directors, and two JPL directors, one NSF director. Basically all the others are high-powered people. They were the previous recipients. If you look at my record, really, what qualifies me to be in that whole bunch of outstanding people? So, I came to maybe that they picked me as a Distinguished Alumni because I have something that few other Caltech alumni have; that is, I have six paintings in the collections of museums! I think that would be something that I can claim, that not many others would have the same [laughs]. Even though there was another alum — actually, he was a graduate school lab mate of mine. He was also named a Distinguished Alum a few years ago. He also worked for Yariv, and also in my field, and he has a distinguished career, too. But his claim to fame is he is an origami expert, pieces of folding papers. He actually put quite a scientific spin on that, basically, to look at a mathematical form of folding. He has written a book on it. His work actually extended to not just folding papers, but folding metal sheets. When you fold big metal sheets, it's the whole sculpture that you are doing. Some of his work has actually been exhibited in the Louvre, in Paris, and also the Metropolitan Museum of Art in New York. I talked to him, and he said that he thinks that his Distinguished Alumni Award also was based on his origami work exhibited in museums. So I think my six paintings in the collections of museums was the unusual aspect that contributed to my selection as a DAA.

ZIERLER: Have you always been interested in art, or is this a more recent development?

LAU: Actually, if you have gone through the PowerPoint that I have put together, my interest in art actually originated in my high school years. Actually, all the work that is currently in museums were all from that period. Actually, all of them were done even before I turned age 16, so I was still a teenager when I did all that artwork. When I left Hong Kong to come to the U.S., I basically hung up my paintbrushes, and I haven't done any painting since then. First of all, I had no more time for that once I got to Caltech. Of course I was overwhelmed with coursework and everything, with my undergraduate education. Then, graduate school, and then to work, so basically it was non-stop in my professional development, so I didn't have any more time for artwork. In recent years, in my retirement, I did go back and created some artwork using software, perhaps, at some point I will put up some of those recent artwork to auction them off as NFTs (non-fungible token).[laughs]."

ZIERLER: I wonder if you've ever thought about if your interests and abilities in art might have made all of your accomplishments in science and engineering possible, if you see bridges between those worlds.

LAU: First of all, I think that it is all about seeing new possibilities, and looking at the same thing at different angles. That really is what it's all about. That would be common if you look at art, and also if you look at engineering and science. You look at the same thing, and look at it from a different angle. "What if this?" Then you try the possibilities. Just go ahead and try it, and see what new things come out. That same principle, I think it applies in all fields, to advance it to the next stage, is to do something surprising. I owe my art pursuit to my art teacher in high school. He was an accomplished artist in his own right. He created a whole new set of artform in ink painting. He was an expert in ink painting. First of all, he did not conform himself to any kind of a particular art form. He didn't classify things as such. He often, like in high school, in class, what he would start us with was, he'd say, "Take a piece of clean paper, and just take a paintbrush, and just start putting some dots and lines on it." Just dots and lines, basic dots and lines, randomly. Then, after a while, you stand back and take a look and see what you have, and then you develop that seemingly random pattern of dots and lines into something, just based on what imagery arising in your head coming from those dots and lines. You create some scene out of it. That basically was his basic approach—start from randomness, and then organize the randomness, to get something that is unique and specific, and that is surprising. I think that there is also some of that aspect in science research and engineering as well. Sometimes, you have to take a step back and take a look at what you have, and then do something seemingly random, but be able to recognize all of the potentials arising from those random things that you create, and then we come up with something that is surprising.

The Value of Rigor at Caltech

ZIERLER: In completing both your undergraduate and graduate degree, essentially your entire professional education at Caltech, what has stayed with you from what you learned at Caltech throughout the years? What did you learn at Caltech that has been so fundamental to what you went on to do?

LAU: Be rigorous, in everything that you do. Don't hesitate to experiment with something that is unusual. Even something that obviously won't work, you may still want to try it. Now, if you do something that obviously won't work, that other people say obviously would not work, and it ends up not working, then you are just—okay, so you are a fool, move on. But occasionally, you try something that obviously won't work, and then, it actually works! That is a breakthrough! That's really what I feel, is that my entire Caltech education is just basically—in a way, you can say that it is a trial and error. Don't hesitate to try new things. What distinguishes a genius from mortals is that geniuses come up with many such breakthroughs over their careers, and mortals comes up with none, or at most, just one such breakthroughs.

ZIERLER: In the course of your career, what have been some of the most important developments in either materials science or engineering in general that allowed you to do all of the things that you did?

LAU: Materials development certainly was extremely important in what I did, because we fabricated laser diodes, and a laser diode really is a very precise fabrication of structures, of different semiconductor materials that you put together that form the device. Without those basic crystal growth techniques, none of this could have happened. The basic crystal growth - the precise crystal growth of those semiconductor structures was fundamental to everything that I did. That's why, when I first started out with Yariv, he put me on learning to row crystals for a few months. Then, I saw that as, it's not grunt work. I saw that as basically a skill that is extremely useful, and very much sought-after. People hire you, like Bell Labs would hire you just because you have that particular skill. So, I started with learning to grow crystal the old-fashioned way – by liquid phase epitaxy - basically archaic by today's standard. Nobody does it that way now. I started with that. Then after a while, Yariv—because Yariv has a very big group, in fact a huge group in comparison. Even in the late 1970s, when I joined his group, he already had like ten or more students. Yariv organized his group very well. Basically everybody would have a different task, and they all worked with each other. At the time when I was starting to learn growing crystals, there was actually already an effort going on—of course, Yariv started that work like ten years or so before I even joined the group, so there were already several generations of senior students already working on that aspect of things. Yariv also kept a steady stream of postdocs coming, and postdocs obviously would supply the group with—postdocs and visitors—would supply the group with new perspectives and also technologies that did not exist in the group at the time. So, it was a very organized effort over there.

After a few months of growing crystals, he decided that, well, the state of development of the semiconductor lasers fabrication in our lab at the time was already quite advanced, and there already were many students working on growing crystals and fabricating devices. He looked at the next stage. "What next?" The holy grail at the time of growing crystal was to try to get a laser which worked continuously at room temperature. At the time, those lasers, they did not work continuously at room temperature. Either you cool the laser down to liquid nitrogen temperature, or you pulse them—basically the duty cycle cannot be too high, otherwise, it would heat up, and when it heats up, it doesn't work. So to work continuously at room temperature was the holy grail of making laser diodes at the time. In the late 1970s, we were already getting close to it, we were already getting some lasers that could lase at room temperature, although not with very high power, and they didn't last for too long, like just a few hours before they conked out. Without working continuously at room temperature, they would not very practical. At the time, when I was learning to grow crystals, the lasers made in Yariv's lab already had proceeded to the point our lasers were at the verge of lasing at room temperature continuously. Once you have that, of course the next step would be to see how fast you can modulate it. Because the whole point of making the laser—the fiber, the development of the fiber, the ultra-transparent optical fiber—was, okay, was to transmit light over many kilometers, without getting absorbed—okay, so the next thing—to transmit high-speed data, you have to modulate the laser, with data you want to transmit, to pulse the laser, to get the ones and zeros to the other end of the fiber. Without an optical source that can be modulated at high speed, the fiber itself would be of limited utility. So really, after you have the fiber, the next big step would be to have a laser. You have a laser, but then you also have to be able to modulate the laser to make it carry some information. That was the next big important thing that needed to be done.

So Yariv put me on it. "Okay, look into it." At the time, people tried to modulate the laser. Now, to modulate a laser is really quite simple, especially for a laser diode : you put a current in; you get light come out. You turn off the current; no light comes out. So, you want to produce pulses of light; just modulate a current. It was a very simple thing to do. But if you pulse the current too fast, the light waveform coming out of the laser doesn't duplicate the electrical waveform In the 1970s, we could not really modulate the light at more than one or two gigahertz. Now, one or two gigahertz, that by itself is already quite fast if you compare it to the electrical cable transmission. If you can deliver just a few gigahertz over kilometers, that would have been fantastic already. The first-generation fiberoptic system was basically running at that speed, at a gigahertz or at least a few gigahertz. Then of course the vision of people was that—the internet of today, basically—they wanted terabits per second. Terabits is a thousand gigabits, it's a million, million bits per second. In the late 1970s, we were still running at just one or two gigabit per second, and people had a much broader vision that the laser-"Now, how far can you push the speed of the laser? Can we do it at ten? Can we do it at 20? How would you design a laser diode that could do it?" Yariv basically put me on the job of figuring out, first of all, what was limiting the laser modulation speed at the time, What were the fundamental things that limit the laser modulation? He put me on that.

ZIERLER: What about in the theoretical realm? What are some theories, either in optics or photonics or quantum mechanics—? Are there any theories that have been very important in your career?

LAU: Maxwell's theory was fundamental to what I do every day. Also when I'm applying all these lasers to microwave and also to wireless communication, I would still regard Maxwell's theory as the key to everything that I do.

ZIERLER: I wonder if you could explain why Maxwell's theory is so fundamental for you.

LAU: Maxwell basically unified electricity, magnetism. If you look at Maxwell's original paper, it's amazing. It was the 19th century, actually. Before Maxwell came along, a number of scientists had done a whole bunch of experiments, observations on various aspects of electricity and magnetism. They observed a whole bunch of individual phenomena. Nobody thought that any of those phenomena were related to one another. There's electricity; if you run current, then you get this electric field. and also a magnetic field, dozens of scientists that came before Maxwell had made a whole bunch of observations about electricity and magnetism, and nobody thought they were related to one another. Electricity and magnetism, nobody thought that they would be related. Until, of course, Faraday showed experimentally that they were related. But it was Maxwell who really put the whole thing together. He took all of those experimental phenomena, and actually formulated them. He wrote down equations that described those experimental results. With a set of like 15 or 20 equations, they each described a different experimental observation. He looked at those equations and actually went ahead to try to solve it, to try to put it all together. Then once he put it together, an amazing thing happened; we got a wave equation! So there's a wave, actually, coming from this electricity and magnetism, and this is all by just a theoretical approach, just by looking at the set of equations, and you solve it. He even predicted that the speed of the wave would be 186,000 miles per second. Then also at the time, some people were trying to experimentally measure the speed of light. They turned out to be exactly what Maxwell predicted to be the speed of this electromagnetic wave. That really made the unification of electricity and magnetism, and light. So light is actually an electromagnetic wave. It all came from that.

So from that deduction, just by taking a step back and looking at everything that we have, that we have observed, and try to assemble the whole thing together, and you predict something new. That aspect is not unlike my art teacher who said that, "Well, just start with a piece of blank paper, you put some dots and lines, random dots and lines." Then you take a step back, and say, what can you make out of those seemingly unrelated dots and lines, and assemble the whole thing into something that is meaningful. That aspect of it I think has a similarity, and I would tend to think that all science and engineering, the development of the science and engineering kind of all follow this same line of progress First of all, you've got a whole set of random facts and observations, and then you take a step back, and you assemble it into something that makes sense out of it. Of course, what distinguished the mortal from the genius is that a genius is somebody who can take a look at things and see the connections and derive new things.

From Hong Kong to Pasadena

ZIERLER: In thinking about your art teacher, let's go back to Hong Kong. Let's start first with your parents. Tell me about them and where they're from.

LAU: Oh, they were from the generation when the Emperor era of China just ended, and a republic was just formed. They both grew up in a small village in southern China.

ZIERLER: In mainland China?

LAU: When they were born and growing up, China was still in the—you know that before the modern China, it was basically an empire. There's an emperor [laughs] in Beijing, and he wielded absolute power. That was back in the dynasty era, so everything was backward, of course. When they were growing up, that was in the very early 1900s, and they just overthrew the very last emperor and tried to establish a republic. Of course, it was chaos at the time, once they overthrew an emperor and then tried to establish a republic. Of course, you have all those warlords running around—everybody is trying to grab power. Everybody was fighting everybody else, so there was a civil war that was going on for a very long time. Then of course when you have civil war, the lives of citizens are basically miserable, and they are all basically farmers, living in small villages. So, there was chaos. Then different factions came out. There was a communist faction, and a nationalist faction, so everybody jockeying for power, and fighting one another. So, there was civil war already happening for—I would say that much of the—starting from the late 1800s to the early 1900s, so continuous civil war. So, the citizens were poor. Then, in the middle of it, Japan invaded, the Second World War. The Japanese came in. Then the nationalists and the communists said, "Hey, let's stop fighting each other right now. Let's fight the Japanese together." Okay, so they stopped fighting for a while, and they fought the Japanese together.

ZIERLER: What were your family's experiences during World War II?

LAU: In World War II, they were already in Hong Kong. I think my father grew up in a village that is just across the border from Macau. Do you know where Macau is?

ZIERLER: Yes.

LAU: Macau. Next to Hong Kong. Just north of the border of Macau, there was a village, and my father would tell me about—he was just a toddler at the time. They were so poor that they didn't even have shoes, in winter, as a kid, he had to walk around with bare feet. Of course, they'd get frostbite and all kinds of things in the winter. So, it was dirt poor. I think at one point he migrated to Macau, and from there, he migrated to Hong Kong. That was when the Japanese invaded, and he told me that the Japanese invaded, and then young men were conscripted to do hard labor for the Japanese army. He told of those experiences. So, now my father—both of my parents—they did not get past elementary school! Basically they just had a couple of years of, in a way kind of like a home village schooling. Basically a village elder would round up a bunch of kids in the village and just start teaching them stuff that they think the kids should know. There was no formal schooling, and just a couple of years of that. So, they did not even graduate from elementary school.

But somehow, my father was very smart. He learned to read and write on his own! Actually, his Chinese calligraphy was better than mine! He even learned to do math on his own. Basically arithmetic. And he was extremely good with his hands, to build stuff and fix stuff. I think that served him well. Then when he went to Hong Kong, he worked at a home garment factory run by his older brother. At some point, he said, "Hey, I can start my own business. I don't have to work for somebody." So he left his brother's garment factory and started his own garments factory. And what you need to start the garment factory, you need some sewing machines. We lived in a flat of a 6-7 story building, an apartment, and he bought maybe a half a dozen or so of those sewing machines and set up shop at home. At the time, there was no electric sewing machines; they were just manual sewing machines, the kind that you work by pumping a foot pedal. So we had about half a dozen of those sewing machines at home. When I was a toddler, I literally grew up playing, crawling around those sewing machines. He hired a whole bunch of—like a dozen or so of those—at the time young girls. who fled China. China was dirt poor, and with the Japanese invasion, and then communists fighting the nationalists, famine everywhere. So a lot of immigrants, they fled down to Hong Kong. My father hired like half a dozen of those young girls at the time. Today, you'd call it a sweatshop. It's a sweatshop operation. Those young girls also doubled up the duty of taking care of me when I was a toddler. I got to know some of those workers, those garment factory workers, fairly well. We kept in touch until I went to the U.S.

ZIERLER: What language or languages did you speak growing up?

LAU: Of course at home we spoke Cantonese, and at school—because I went to school and I learned English, but at home, we never spoke English, because no one at home spoke English. Cantonese was my principal language, my mother tongue.

ZIERLER: Tell me what kinds of schools you went to, growing up.

LAU: My elementary school was a Catholic school. In Hong Kong at the time, the education system was such that your goal was to go to university. Everybody's goal was to get to university. They thought that after you go to university, you'll get a good job, you'll have a good life, and you were set for life. But, on the other hand, at the time, there was only I would say two major universities in Hong Kong. Of course, competition was extremely tough trying to get into those universities. You had to pass exams to get into them. To increase the chance that you get into them, you have to start with a good kindergarten. You start with the kindergarten. Now, it's even more competitive, but even back then, even to get into kindergarten, you had to pass some exams. I don't know how they examine toddlers, but they have some interviews, to be examined, before they admit you to the good kindergarten. So you've got to go to a good kindergarten, in order to get into a good primary school, in order to get into a good secondary school…. At every stage, you had to take exams, usually public exams, to get to the next stage. The Catholic schools at the time were considered some of the better schools.

My mother was the one who paid a lot of attention to m' education. My father always adopted the attitude that education—nice if you have it, but if you don't have it, you still make a living; what's wrong with that? He didn't have a good education, and he made a living OK, so, don't force yourself. He always said, "Just go naturally. Just do what you can. Don't force yourself." My mother, on the other hand, said, "No, you have to force yourself. [laughs] If you don't understand something, stay up at night and try to understand it, and do the homework." My mother was the enforcer, in a way, at home. My father was the one that basically—he would be the one giving me enjoyment and entertainment. As a reward for me doing well in school, my father would—he knew that I—even when I was very young, I was fascinated by—the kind of toys that I would like to play with was actually those model tanks and model battleships, but the kind that come in a hundred different pieces, and you buy them, and you glue them all together, and you put in a motor, and make them run. Those things fascinated me even when I was young. So my father, as an enticement to me to do well in school, he said, "Well, if you place first, or you place within the top three in final exams I'll reward you by buying you this model of the battleships," which I loved. Every time he took me to those shops, department stores really, I would linger at the section where they sold those battleship models, so he knew that I loved those things. Then, when we bought a battleship, my father would—because he wouldn't let me just play around with the thing, because as a kid, if I were to glue things together, I'd glue it all wrong, and then it's not reversible once you glue it. So he would guide me through how to assemble the whole thing, and put in the motor, gears, propeller, and then make it run.

After we put in the motor, we took it to the pond. There was a pond not so far from our house that a whole bunch of kids would basically take their own models to sail, in the pond, basically to compare with one another. "What do you have?" To show off what you have. Then there were some incidents where—I still remember the battleship that I had, it was HMS Hood. The Hood, that was a British WW II battleship. Then I put it in the pond, and set the motor running, and it sailed off into the pond. Then one time, right in the middle of it, there was another kid—he had a Bismarck—and so he saw my Hood coming, and he launched his Bismarck to broadside me. Then the Bismarck broadsided my Hood I just saw the Hood kind of shuddered, some, and then boom, it rolled over and sank in the middle of the pond! [laughs] Then my father had to pay another kid to roll up the legs of his pants to wade out into the pond to salvage the sunken ship. We took it back home, and of course we had to take it apart and do some major repair and renovation to make it work again. Then I told my father, "No, this thing is too wimpy. It sails way too slowly." And that we had to put in a more powerful motor, and more powerful battery, and more powerful propeller. My father said, "Okay." We go to the department store again, and bought a whole set of the motor and a new set of gears, bigger batteries and a new propeller, all new. So basically making it a more powerful ship.

What impressed me was that—the new propeller was a much bigger propeller than the one that we had before. Now, of course the propeller shaft had to go through the ship's hull, and the original opening in the hull didn't fit, it was too small, what do you do? Of course, if we had a drill, you drill a bigger hole to make it fit. But we didn't have a drill at the time, and so my father took a screwdriver, went into the kitchen, heated up the screwdriver on a stove, and basically stuck that into the small hole to melt the plastic mold and made it big enough for the new propeller shaft. Then of course it wasn't a tight fit, so we had to pot the hole with epoxy to make sure that the water didn't leak in. That was an improvisation, basically. We didn't have a drill to properly make the hole. But he used what he had to make the thing work. So [laughs] we have a powerful ship now— a powerful propeller, a powerful battery, and a powerful motor. We went back to the pond, and looked for the Bismarck for revenge. [laughs] We wanted revenge. But we never saw that kid with the Bismarck again. So history did not repeat itself – in WW II, the German Bismarck sunk the British Hood, and the British fleet went after the Bismarck and eventually sunk it, avenging the loss of the Hood. Anyway, that whole experience taught me the value of improvisation. That improvisation actually was—now, in my graduate school, when I was looking at how to build a high-speed laser, how to make a laser that could be modulated at higher speed than anybody else, there was one critical experiment that I did that required improvisation. It looked clunky, but at the end, it worked. It proved the principle. That was one lesson I think that translates.

ZIERLER: In high school, did you excel in math and science?

LAU: I would say that over my entire elementary school and in high school, I was quite good in math and science, but I wasn't the top. In every class, of course there were always one or two really, really smart kids, that consistently ranked first. I wasn't one of those. But I was among the top quadrant quite consistently, all the way. It was actually in the last two years of my high school —in the Hong Kong system, it was a British system, so you go through—here, it's K through 12, basically. That's elementary to high school system. There, they have six years of elementary school, and then five years of high school, and then plus two extra years, before you actually go to university. Of course, in every stage, you have to take public exams to get to the next stage. In the last two years, that was when you specialized. Before the last two years, basically until you get to the 11th or 12th grade, the education was general. There was no specialization. You learn everything. You learn chemistry, you learn physics, you get biology, you learn math, you get literature, everything. Then your last two years of the high school is when we specialized. We went into different classrooms, basically. There's a class that specialized in literature. There's a class that specialized in biology. There's a class that specialized in math and physics. I went in the class that did the math and physics. Those who went into biology would eventually become doctors; they'd go to medical school. Those who went in literature would become lawyers. They went to law school. So it was only in the last two years, in the specialization, that I found myself excelling. I managed to actually took the first place in the final exam for the first time, ever, in my entire elementary and high school education. That was when the specialization was in math and physics.

ZIERLER: How did you get the idea to apply to Caltech?

LAU: That was totally accidental. I was just walking home one day from school, and I passed by a bookstore. I just walked into the bookstore, and kind of just randomly browsed at books, and just randomly pulled out a book from the shelf. The book turned out to be a biography of Tsien Hsue-Shen, who I have mentioned in my PowerPoint. Tsien Hsue-Shen was a Caltech Ph.D. graduate. He was von Karman's student. He was recognized as a rocket and missile and rocket expert in the U.S., became a professor at Caltech, and a trusted advisor for the U.S. military to develop missiles and supersonic aircrafts (together with von Karman) and then in the McCarthy era. He was persecuted as a suspected communist, was eventually deported to China in exchange for a dozen captured U.S. airman in the Korean war. Of course, Chairman Mao was delighted! "Welcome, welcome, welcome. Of course." So, Tsien Hsue-Shen was given all the resources to start an aerospace program for China. He was known as the father of Chinese rocketry, and he brought rocketry to the Chinese. The entire Chinese space program today all had the beginning from his work starting in the 1950s, thanks to Joseph McCarthy.

So, I read his biography. Of course, what captivated me was that on the very first—just on the inside cover of the book, the first page of the book, it says, "Missile expert : Hsue-Shen Tsien." Of course, what teenager boy wouldn't be fascinated by rockets and missiles? I said to myself, "I want to be a missile expert, too. So I'll follow his footstep. I'll go to Caltech, too!" That was really what inspired me to come to Caltech. That's why in the PowerPoint presentation I sent you, in the beginning the title was, "In the Quest for Speed." Because originally, I came to Caltech thinking that I would major in aeronautics and follow in Hsue-Shen Tsien's footsteps and major in aeronautics. Not long after that, some of my other classmates from Hong Kong said, "You are not a U.S. citizen, so we're not sure that you're going to be able to stay in the U.S. after you've graduated. If you go back to Hong Kong"—or even China at the time—there was no aerospace industry so there would be no jobs.

Now, getting a good job after graduation actually was important to me, was a strong motivation, because my aging parents, even though they were doing okay, they were by no means well-to-do. Actually my parents—my father actually had to devote quite a bit of the resources he was planning to use for his retirement just to enable me to go abroad to study. So, finding a good job after I graduated to support my aging parents was an extremely important consideration for me. So, I thought, I need to get into a discipline in which I can find a good job without trouble in the U.S. Or even in Hong Kong, because I wasn't sure that I could stay in the U.S. at the time. That's how I switched out of aeronautics at the time, and I started looking at, "What else is interesting? Well, electrical engineering, that is something that I like." In the Electrical Engineering Department there was a library, that was basically open to all students 24x7. You could just walk in, and browse around at things. I saw this thing called fiber optics that was then totally new, It was in the mid to late 1970s. It was totally new at the time, and I said, "Oh, this looks interesting." Actually, I was interested in physics, too, but physics by itself sounds too academic —engineering is something that I thought was something that you could find jobs. I said, "Okay, here is something that is practical yet has a very high physics content in it." Of course when I delve into it, the entire field of semiconductor electronics was very much physics-based. So I got interested in electrical engineering and in particular in fiber optics, quite early on.

When I switched to electrical engineering, I was assigned to an advisor. There was an undergraduate advisor. There was an advisor that was assigned to me. I still remember that the executive officer, or the equivalent of the department head of Electrical Engineering at the time was a professor called Hardy Martel. I just saw that he passed away, now a few years ago. He asked me, "Okay, I need to assign an undergraduate advisor to you. What are you interested in?" I looked at the catalog and said, "Well, there's this discipline called "communications and control". This looks interesting. Communications and control." He said, "Okay, good. John Pierce. I'll assign you to John Pierce." So I went knock on John Pierce's door, and he took me in. I didn't know it at the time, but John Pierce was an extremely well-known electrical engineer. Before he came to Caltech, he was actually an executive director at Bell Labs. He was known for… inventing satellite communications. He was known as the father of satellite communications. So, that was interesting to me. He was at a very high level executive position at Bell Labs before he came to Caltech. So, he took me on as an undergraduate advisor.

The first thing I asked him was, "I want to find a job. Do you have a job for me in your lab?" He said, "Okay, all right. I have a student who is building this circuit"—or what they called a vocoder at the time. Actually, it's a kind of a voice coder. This graduate student needed some help in building some circuits, so I was assigned to building, soldering, circuit boards for him, even though up to that point I had not handled a soldering iron before, and I didn't know how to solder. John Pierce was an extremely well-known electrical engineer. Basically everybody at Bell Labs knew of him. He was extremely well-connected to Bell Labs. After the first summer, I built vocoder for the graduate student – a rack full of equipment which apparently John Pierce was quite happy about. He was teaching a graduate class at the time, and he asked me to haul that entire rack of equipment into his class to demonstrate how it worked: I was still an undergraduate back then. So, I did that. Then, the next year—that was actually in my junior year now, and at the end of my junior year, he asked, "This summer, what do you want to do in my lab?" I said, "I saw this thing, fiberoptic communication. It sounds quite interesting. I want to do something with that." Pierce said, "Well, I am not doing much of that at Caltech right here. But, on the other hand, I know a lot of people at Bell Labs who are doing that. Why don't I introduce you to some people at Bell Labs to work for the summer?" Of course, I was ecstatic. I got a chance to go to Bell Labs to work! Pierce basically turned around and picked up the phone right there, and apparently called someone or some lab director at Bell Labs. In five minutes, I just walked out of the office with a job in hand, at Bell Labs for the summer! That was the summer of 1977, at the end of my junior year that I went to Bell Labs and did my first summer work there. The result of that first summer was quite satisfactory, in that I got my first paper and my first patent, out of that summer's work.

The second summer came along. I was graduating with a B.S. degree from Caltech. Pierce asked me, "What plans do you have for graduate school? I said, "Well, being a graduate student at Caltech sounds quite interesting." Because I worked with graduate students and I saw all the interesting things that they were doing, and that it was a good life. So—"I want to stay at Caltech." He asked me to just apply to graduate school at Caltech, and so I applied, and was admitted. Pierce basically picked me up as a graduate student as soon as that happened. Then, what do I do as a graduate student? Pierce said, "Well, how about if I make the arrangement for you to go back to Bell Labs to do your thesis?" So for the summer of 1978, I would go back to Bell Labs Holmdel and working in the group that Pierce made arrangements for me to spend the next three or five years, or whatever number of years, to finish my thesis at Bell Labs, and Pierce would continue to supervise me, at arm's length, while I would be working with a scientist at Bell Labs to do my thesis. Basically, that arrangement had been all set. So that second summer when I went back, I was actually working for this person that potentially would be my thesis advisor at Bell Labs. Then I went back to Caltech after summer was over, I was all prepared to make my trip back to Bell Labs the following year and spend whatever number of years I needed to finish my thesis there. The person at Bell Labs said, "Let's find a studio for you to live while you're working here, and get you a used car to get around." All the arrangements had been made for me to go back to Bell Labs. In the fall of 1978 was I went back to Caltech to make all the preparations, basically finish up all my course requirements and to take the qualifying exam, getting rid of all of those requirements and prepare to go back to Bell Labs. That's when I ran into Amnon Yariv in the hallway one day. Now, Yariv, he knew about my work at Bell Labs the previous summer, and he was interested in getting me to work for him. So when he ran into me in the hallway, he asked me, "What plans do you have for graduate school?" I told him about this arrangement, that I'm going to Bell Labs to do my thesis. He said, "Wait a minute, not so fast. Let's come to my office and let's talk." Then he went ahead and told me that it's SUCH a bad idea, to go to Bell Labs. He said it was a much better to stay and work for his group instead.. Of course, nothing beats the weather at Caltech.

Meeting Amnon Yariv

ZIERLER: Was this your first interaction with Amnon? Had you seen him or known him before?

LAU: Actually, I think that I would say, yes, that was my first serious interaction with him. time. When I came back from Bell Labs Crawford Hill the first summer, I showed him what I did, he seemed impressed, and asked me to present a seminar to his graduate students and postdocs at his group meeting. Then after my second summer at Bell Labs, when I was about to go back to Bell Labs Holmdel to do my thesis, that's when he intercepted me in the hallway, and told me that I should work for him instead. There were various factors under consideration, personal and otherwise. Eventually I decided to stay and work for him, and I told Pierce, "No, I'm not going to go to Bell Labs. I'm going to stay." He wasn't too thrilled [laughs] when he first heard about that, but he understood and respect my personal choice. Pierce and I stayed in touch. Until even after I graduated with my PhD, I still stayed in touch with Pierce, until at one point he left Caltech and went to Stanford. He went to Stanford as a Professor of Music, surprisingly. So, I stayed in good relation with Pierce, and I started working with Yariv. That was in the fall of 1978.

ZIERLER: Just to imagine, if you had stayed at Bell Labs with the original plan, what would you have done? What would your thesis have looked like?

LAU: It's really hard to tell, because once I'd go to Bell Labs, of course, there were a whole new set of circumstances, a whole new set of opportunities presented to me, a whole new set of people I interacted with. I don't know if I would have stayed and done the high-speed semiconductor lasers as I would have done at Caltech, even though the high-speed semiconductor lasers were also a topic that Bell Labs was seriously pursuing at the time. It's possible that I also would be doing similar kind of topics, but with a whole new set of circumstances and capability available, of course. So it's hard to tell, really. I would say that if I had gone to Bell Labs to do my thesis, then I probably would have stayed at Bell Labs to work after I graduated, and my whole career path, the whole trajectory would have been different.

ZIERLER: What was Amnon Yariv's research group focused on when you joined? What were they working on?

LAU: Yariv's group at the time, there was two main areas. The first was these semiconductor lasers, which was what I worked in. The other major topic was in non-linear optics. So, there were two major efforts at the time, and one really didn't have a direct relationship with another. As I said, I started learning to grow crystals, for how to make semiconductor lasers. But at one point, like after a couple of months, Yariv saw, first of all, that there were already too many students working on making lasers. Then also the state of lasers at the time was already on the verge of being able to run continuously at room temperature. That's the time that he directed me to looking at high-speed modulations. Now, to do high speed modulation at multi-gigahertz rate requires some expertise in microwave instrumentation. There was a problem at the time that we didn't have any microwave instrumentation or expertise in the group, at the time. Yariv, of course, has an extremely high reputation worldwide. He always attracted the top people from everywhere to come and visit. At the time, there was an Iranian professor Hossein Izadpanah of Shiraz University was visiting Yariv's group, and he brought with him a strong background in microwave instrumentation. I worked with Hossein and started this effort in high-speed modulations of lasers. At the time, we di find some World War II era microwave equipment in the campus surplus, very, very old equipment, and came back and then just started playing around and did some very rudimentary experiments with modulating lasers. We were making good progress. Except in 1979, while Hossein took a trip back to Iran to take care of some business at his university, embassy was taken over and the ensuing hostage crisis erupted. Of course, Hossein could not get his visa to come back to the U.S.

So now, what do I do? I relied on him to learn about microwave instrumentation, and now he was not here. Yariv happened to be consulting at Hughes Research Lab at Malibu at the time, working with a group that included Luis Figueroa, Hwan Yen (a former student of Yariv) and Charlie Slayman on the topic of "microwave-photonics interaction", of which high speed direct modulation of laser diodes was a main theme. So one time when he went to consult at Hughes, he brought me along and introduced me to the group over there, and basically got me to collaborate with them. One of them, Luis Figueroa, a Berkeley graduate. was extremely nice to me. Of course, at that time, I didn't have a car. Luis Figueroa was extremely nice to me. He lived in nearby Woodland Hills at the time. He offered to actually come to Pasadena to drive me back to Hughes to work. So, he would come to Pasadena, drove me back to his home in Woodland Hills. We stayed for the night at his home, the next morning, we went to work at Hughes together. Then after work, he actually drove me all the way back to Pasadena. then back at Caltech, I'd work on the theory of our experiment . This collaboration resulted in my first few major publications (after my first paper from the summer's work at Bell Labs) that became a significant part of my thesis.

Now let me go back to when I was still with John Pierce, who of course, also had an extremely high reputation, and he had collaborations with a wide range of people. One of them was Edward Posner, the chief technologist of the Telecommunication and Data Acquisition directorate at JPL, responsible for the operations and developments of the Deep Space Network (DSN), on which all interplanetary missions of JPL rely. I knew him very well, while I was working on my thesis in Yariv's group, Posner came to me and said, "Hey, JPL wants to develop an ultra-precise fiber-optic frequency and timing transfer system for synchronizing antennas 10s of kilometer apart at the DSN. At the time, it was being done by cables, by coaxial cables, or free space microwave links, both of them were sensitive to environmental variations, and this gravely affected the ability of the DSN to track and navigate deep space spacecraft extremely precisely, a capability needed for many planned missions in the future. There was a fellow at JPL (George Lutes) who had already started a program since a couple of years earlier. But they needed more hands-on expertise to make further progress. Ed Posner was aware of my work in high speed lasers and microwave fiber optics, so he came to me and said, "Hey, would you be interested in helping out at JPL on a part time basis" I said, "Okay, I'd be very interested. But first I have to ask Yariv, to see if he allows it." Yariv usually did not permit his students to go to take on outside work while they were still working on their thesis. preferring his students to spend all their time and effort in finishing their theses as fast as possible, not to get distracted on outside work. So, when I talked to Yariv, I told him that, "Well, there's this job at JPL that I was asked if I'm interested in, and actually it looks like it has a lot of benefits to my thesis work." I managed to convince Yariv to let me take a part-time job at JPL. That's how I got involved with JPL. The person at JPL I worked closely with, George Lutes, was a very interesting character : he had not finished college, but taught himself over the years to become an expert in microwave technology. so I thought that's a good opportunity for me to learn more about microwave technologies and instrumentations.

Eventually I convinced Yariv that I could take a job at JPL. There was a shuttle between JPL and Caltech, that went back and forth every day, a few times a day. So I took the shuttle to JPL to work at JPL. I still didn't have a car at the time. That went on for a while, and so that's how I got me started at JPL. That project eventually, produced the fiberoptic system for synchronizing antennas, the Deep Space Network, which turned out to be very important in that it enables the extremely precise tracking and navigation of all JPL spacecrafts. It's a capability that JPL had before, but going forward they needed the high precision to be able to execute some of the more demanding missions being planned, including rendezvous and landing on a comet the size of a stadium zipping around at the edge of the solar system millions of miles away at thousands of kilometers per second. Over the years, that system had undergone many upgrades, but the basic ultra-precise fiber synchronization system that George Lutes and I developed in the late 1970s remains in operation today.

I began working on this effort at JPL in the summer of 1979. In short order, the basic framework of this system had been established. At the end of the summer. I told the department head at JPL (Dick Sydnor) that I needed to go back to do my thesis full time, I couldn't continue to work at JPL anymore. Sydnor said, "Well, let's see. You've got a really good thing going here at JPL, and its really important for JPL's entire mission of interplanetary exploration. I'll tell you what, let me talk to Yariv." So, he told Yariv, "How about if JPL would give Yariv a research contract to support my graduate assistantship at Caltech. Basically JPL would be supporting me at Caltech, in exchange, I would work at JPL for two or three days a week during the school year, and full time during summers. And, to sweeten the deal —"I know that Kam didn't have the advanced microwave equipment at Caltech for Kam to finish his thesis. How about if I loan you the microwave equipment from JPL, so Kam can finish his thesis even aster with JPL's equipment?" So he worked out a contract with Yariv, first to fund my graduate research assistantship at Caltech, and second, to loan me the microwave equipment at JPL. Yariv said, "Well, it's a good deal. Let's take it." So the arrangement was made for me to continue my work at JPL for a couple days a week while I was finishing up my thesis. That was from 1979 to 1981. So by 1981 I had my thesis and the basic framework of the DSN fiber system design all finished up at the same time.

High Speed Lasers and Business Opportunities

ZIERLER: What do you think were the main contributions or findings in your thesis?

LAU: The main contribution, I would say that I laid out the basic principle on how to make a high-speed laser, how to make a laser modulate fast. So all the basic principles were laid out in my thesis work. Now, to actually implement it, to actually build a high-speed laser, of course that came later at ORTEL—to actually implement the work that I did at Caltech, and to commercially produce them. Again, as I said, the impact of the work, you cannot really get to the fullest extent until you put the stuff that you built in the hands of the user, that they can use it for many different applications. So that was ORTEL. So that was from 1979 to 1981, that I was finishing up my thesis at Caltech at the same time I was also finishing up synchronization system in the Deep Space Network, at JPL.

Now, by 1981—at the time I graduated—of course once you've graduated, you go out and look for opportunities for jobs. I went to interview at the standard places at the time, like Bell Labs, Lincoln Labs. I got several job offers from them as well as from industries. JPL also gave me a job, to try to get me to stay and work permanently for them. I think I was just about settled on going to Lincoln Labs in Boston. That's when Yariv intercepted me again. He said, "Well, what sort of job offers are you getting right now?" I told him about all the places I was expecting offers from. He said, "Well, let's come to my office and talk." [laughs] So I went to his office. He told me that there was this company he was starting, with another postdoc and another graduate student, at the time. This was ORTEL of course. He asked me if I would consider taking a job there as the company's first employee,. Actually, at the time that he talked to me, they didn't even have the funding in place. They were still looking for venture capital at the time. Basically the company existed only on paper. when Just as we were finishing up the meeting with Yariv, Israel Ury, another of the co-founders who was a former graduate student of Yariv, called from New York, and said, "Guess what? I just talked to the venture capitalist, and I have a million-dollar check in my pocket right now. I'm coming back!" Also in Yariv's office at the time was a postdoc , Nadav Bar-Chaim, who was another cofounder of ORTEL, he quipped "Make sure Israel makes a beeline back to Pasadena. That he didn't make a detour to South America with the million-dollar check in his pocket! [laughs] So, that was the beginning, of ORTEL.

So twice in my career, Yariv intercepted me and changed the trajectory of my career forever: first not to go to Bell Labs, and second to basically get me to work for his company, ORTEL.

ZIERLER: What was your initial position at ORTEL? What were you responsible for?

LAU: My initial title was staff scientist. Of course at the time there wasn't another scientist that was in the company. There was a president, who was another of Yariv's students, and there was a vice president, who was an Israeli postdoc of Yariv. So there was a president, there was a vice president, and then Yariv was the chairman of the board. And then there's me! So I was a staff scientist, but I was the only scientist. There wasn't another scientist in the company until like three or four years later. Basically, by default, I was chief scientist, except I was chief without anybody working for me! As I look back, I think the reason they wanted to get me to work for ORTEL was because, first of all, my expertise was not in making lasers and growing crystals. That was the expertise of the other Israeli postdoc and also the other student. Basically I think why they wanted me there was because of my high-speed modulation expertise. Because at that time, in 1981, there were already a few companies in laser diodes around. Still the entire field of fiber optics was still extremely early in the game. And so, there was a few companies already selling laser diodes, and we had to distinguish ourselves. What differentiated us from the other existing companies? I think they had in mind to build high-speed lasers. We had to build lasers that can be modulated at higher speed than any other company. And that's why I came in. That's why they wanted to recruit me.

ZIERLER: Did you see yourself as leaving academia at this point? Did you have an idea that you would one day become a Berkeley professor?

LAU: No. At that point, in 1981, just to remind you, just getting out of school and then jumping straight into a startup was still very rare. In 1981, I think Apple was just founded just a couple of years earlier. I think they still just had the Apple I computer. So all those startups, IPO and all those big companies in those days. At the time after you graduated from a PhD, the standard thing to do was to go to Bell Labs and work for your life, and to publish papers. That's what it was. Joining a startup at the time was perceived as extremely risky. Some other person, or some others sometimes would say, "Hey, how do you know ORTEL will exist after two years?" So, I went up to talk to Israel Ury. Israel Ury was the other student of Yariv who was the cofounder of ORTEL. He was the president of ORTEL. I asked him, "Well, how stable is the company? What do you think will happen to the company after two or three years? Are we going to run out of money or what?" Israel Ury said, "Well, look, try this for a few years. If it doesn't work, you think Bell Labs wouldn't give you a job? Bell Labs is something you can always go back to." So he convinced me to basically take it on, and give it a try. Once I was at that stage, the thought of going back to academia did not occur to me at the time. Because I saw that—like Yariv; he started off his career at Bell Labs. Also, another professor at the time was Bill Bridges. Bill Bridges came from Hughes Research. Bill Bridges was the inventor of one of the more important lasers, the argon ion laser. But he started his career also—well, I think he started his career at Hughes, and then later on—so both Yariv and Bridges, they both started their career in industry, and then after they built a sufficiently good reputation, a big reputation in industry, then they went back to academia.

Also, at the time, you'd hear all kinds of horror stories about academia, that you go there and be an assistant professor, and you don't have tenure, and then you have to fight for tenure, and so you have to basically build a program and do a good job in teaching, and administrative things, a thousand things that they pile onto you, that you have to do well, before you get tenure. So the reputation at the time was that it's a hard life, when you go to academia, as an assistant professor. I looked at Yariv and Bridges. Those were not hard lives. They came to academia with tenure, basically as a full professor. I told myself, "That's what I really want to do. If I ever go back to academia, I want to go back there after I build a record, and then I'll go back to the university, tenured, just like Yariv and Bridges."

ZIERLER: What do you see as your most significant achievements at ORTEL?

LAU: I think that I enabled ORTEL to, in a way, launch what is known as the microwave photonics market, basically microwave applications of fiber optics. That became big first when the cable industry materialized, first cable TV, and then cable internet. That became a big market. Then second, the same technology, once you're able to transmit microwaves with high fidelity over optical fiber, you can also transmit wireless signals through it. That was the second major application, is wireless fiber optics. The wireless connections would allow you—because at the time, people were using mobile communication devices, but they were still all complaining that, yes, the wireless communication works well outdoors, but as soon as you walk into a building or go underground into a parking garage, you got cut off. That was a problem at the time. If you're able to route wireless signals through fibers, then you can basically get the radio wave everywhere that you are going. You never will be cut off again. Overall, that entire field is what one calls microwave photonics. I think the high-speed lasers that I did at ORTEL was the device, was the key element, that enables you to transmit microwave through fiber. I see that as my legacy, really. Eventually, of course, there are other ways to transmit microwave, too, but we were the first, ORTEL was the first, to be able to transmit microwaves with high fidelity through optical fibers.

ZIERLER: What were the circumstances of you moving over to Berkeley, to reentering academia?

LAU: Again, as I said, when I went to ORTEL, I was looking at Yariv and Bridges as a model for building a good reputation in industry, and then at some point moving back into academia. Yariv and Bridges were my models. By about 1988, after seven years now with the company, with ORTEL, I saw that I had built a substantial reputation now, in my research. Also ORTEL at the time was already mature, so moving into the manufacturing phase, even though there were still substantial opportunities for research at ORTEL. But I saw that the time was right for me to move into academia. In a way, I kind of followed the footsteps of Yariv and Bridges.

ZIERLER: Did you see the move as an opportunity to change your research, or were you continuing in the same trajectory?

LAU: I definitely saw academia as a way to move into something new. But of course, once you moved to industry, people hire you because of what you have accomplished, your track record, so they expect you to continue for a while, before you switch to something new. But yes, I did expect to be able to move on to something new, which I eventually was able to do when I moved to Berkeley.

ZIERLER: Tell me about that new research. What did you take on at that point?

LAU: At Berkeley there was another professor there by the name of Richard Muller, who was one of the pioneers in micromachining. Actually, I don't know if you know Yu-Chong Tai, at Caltech?

ZIERLER: Yes.

LAU: Professor Tai, Yu-Chong Tai. He was Muller's student, and he was a Berkeley graduate as well. So, micro-machining, and I was thinking of, how do you apply some of those micro-machining techniques to optics. So, at Berkeley, I started a program with Professor Richard Muller on micro-machine photonics. That was something that I launched with Richard Muller at Berkeley.

Longstanding Partnership with JPL

ZIERLER: When did you get involved with the Deep Space Network?

LAU: That was from when I was still a grad student of Yariv, and then when Ed Posner, who was JPL's chief technologist on the Deep Space Network, recruited me to work there part-time. That was my first interaction, with JPL and my involvement with JPL.

ZIERLER: Did you stay involved with the Deep Space Network when you were a professor at Berkeley?

LAU: Loosely. I was still in contact with George Lutes, my collaborator at JPL. As I mentioned, the basic system design was already finished when I graduated and left JPL and went to ORTEL. The basic system design was already there. But to implement the system, actually install it in the Deep Space Network, required the field deployable components and systems, the kind of hardware ORTEL built. So when I was at ORTEL, that was at the time when JPL started deploying this system. There were three major sites of the Deep Space Network—at Goldstone, and also in Australia, and also near Madrid, in Spain. So it's at the three sites of the Deep Space Network that they started implementing and actually installing this system in all three DSN sites around the world, in the late 1980s. That was the time when ORTEL really began production of these microwave fiberoptic systems and components. So, we stayed in touch.

ZIERLER: Tell me about your involvement with the Galileo mission to Jupiter.

LAU: That one actually was an outgrowth—that happened in 2000, right? The Galileo, the spacecraft itself, it was actually built a few years before, and it was supposed to be launched on a space shuttle. Then of course after the Challenger explosion, the space shuttle program was canned. Not canned, but at least frozen, for a few years, when they tried to figure out what was wrong, to get it back to order. So I think the JPL people thought that basically because the spacecraft was in storage for a few years before it was actually launched, and so there's a mechanism there, that the antenna of the Galileo—there's a big antenna that was a major communication antenna that allowed it to transmit at high bit rates. Actually, it's like an umbrella. It opens up to be a bigger antenna. So when you launched, you had to fold it up, because when you launched, you had to fit into a space shuttle bay, so there cannot be a big antenna in there. After it gets to Jupiter, then the antennas open up like an umbrella. Of course, after the long journey to Jupiter, when it got there, and JPL told it, "Open up the antenna," it wouldn't do it! It got stuck.

People thought that during the long storage, before it was actually launched, maybe some of those hydraulic fluids leaked out. So, it wouldn't open up. So now, what do you do? Now the spacecraft is out there, half a billion miles away. What can you do? Actually, not much. They can change some of the programming of the coding, of the signals being sent, to try to make it more efficient. But on the other hand, without the big antenna, you really cannot get the high data rate transmission. Now, in addition to the big antennas that was intended for data transmission, but then there was also a smaller antenna at Galileo. That was not a directional antenna. It was also an antenna, but on the other hand, it's not a high gain, meaning that you cannot really do high speed transmission — it's an antenna that is intended for sending telemetry information, basically informing JPL where the spacecraft is, basically what is the status of the spacecraft. It's not intended for high-speed data transmission. That thing can transmit, but at a much lower data rate. So they still have that small antenna, but that small antenna, with the existing Deep Space Network configuration, they can only transmit like 8 to 16 bits per second, not megabits for second.

ZIERLER: Right, really slow!

LAU: It's really just to transmit telemetry data. They could still use that for transmitting data, but they figured that, well, they've got these terabytes of data that they got from the encounter with Jupiter, and now, how long does it take for—at 8 to 16 bits per second, how long does it take to transmit all the data back? I like to say that, even if we Earthlings had the patience to wait—but the spacecraft is heading out, in the solar system. It's moving further and further away, the radio isotope thermoelectric generator on board the spacecraft would have run out before all the data gathered at the Jupiter encounter could be sent back to Earth. So, all the terabits of data at the Jupiter encounter would be lost. This would be a total mission loss, in a way. That's how JPL figured out that, well, since we can't do much about the spacecraft itself—it's already way out there—but we can do something about the receiving antennas, and that's the Deep Space Network. Using the arraying capability that the system that I and George Lutes built at JPL, at least we tried to increase the data rate coming back, with this spacecraft still transmitting using only the small antenna.

ZIERLER: What were your contributions to the Shuttle Radar Topography Mission, also in February 2000?

LAU: That is again an outgrowth of the basic system that we developed for the DSN. Now, the shuttle radar mission was about topography mapping of the Earth's surface, land surface. That was done by using two antennas on the space shuttle itself. The two antennas working together would produce an interferometric effect, so you can measure also not only the intensity of the radar reflection but the phase as well. And with the phase of the reflected radio wave, you can tell the altitude. You can basically get not just the space spatial fearure of whatever you're looking at, but also the depth information as well. You can get three-dimensional information about the surface of the Earth by using two antennas. These two antennas, the way they work, the two antenna have to be spaced quite further apart. Well, how far can you space it apart on a space shuttle? Not much. A space shuttle is only yea big. On that particular mission, they had an extendable boom, basically a mast, that you can just pull out like an antenna. You can pull it out to 60 meters long. Yeah, I think it's 60 meters long. That whole thing, first you compress it all together like an accordion, and stuff it in a canister inside the shuttle bay. In orbit, you pull it out, and then that's the 60 meters long. So there are two antennas. One is sitting inside the shuttle bay, and one is sitting at the far end of that long 60-meter boom.

Now, the two antennas again have to be synchronized; otherwise they cannot work together. So, they needed a means to synchronize the two antennas, over 60 meters. Of course, you can use a cable, but the cable has the same problem as the DSN cable—the space shuttle is running around the Earth in orbit, so basically it either goes into the sunlight, or it goes in the shadow, so you've got a continuous temperature cycling basically—sunlight, shadow, sunlight, shadow. I think it's a 90-minute orbital period. Every 90 minutes, you go from sunlight into the shadow, so they could not have the two antennas work together as the interferometer unless you have more stable synchronization between the two. When they followed the DSN system that we built at JPL, they said, "Well, maybe if we can adopt that system, just a miniature version of that system, to put a fiber on the space shuttle boom, and then basically synchronize it, just like the way we do it at JPL, at the DSN." Actually, that happened; I think the mission was launched in 2000. By that time, I already left JPL. I was already at ORTEL. But my colleague at JPL, George Lutes stayed at JPL, and so he was the one who actually would put the thing together, and put it in shuttle flight. But the technology was still the same as—it was very similar to the one that we used at the DSN a decade ago.

Breakthrough in Wireless Mobility

ZIERLER: How did LGC Wireless get started?

LAU: That was after I went to Berkeley. I started looking at some other applications of the radio over fiber. Now, you have the ability to transmit high-fidelity wireless signal over fiber. What else can you do, other than cable? Again, everybody at the time had the experience—cell phones were already existing at the time, although the reception wasn't always satisfactory, especially inside buildings. Once you'd walk inside a building, and especially at the lower floors and the basement, you got no reception. That wasn't a very satisfactory experience. Also with the internet coming, wireless is not just talking; you've got data on the wireless as well. You don't often surf the internet while walking around town. Most often you use the wireless network actually when you're inside the buildings, when you sit down, and then you really download and look at movies and those kinds of things. It became obvious that there was a need to figure out what to do with this in-building wireless reception. I think that Cory Hall, which was a building at Berkeley, the EE building at Berkeley, is typical of the older buildings. They are concrete rebar. It's a concrete building and then all those metal bars inside the building. It's really unfriendly to radio wave propagation, so the reception was quite bad, actually. The wireless reception was quite bad inside the building. We said, "Well, since we know how to route a microwave radio through fiber, why don't we put an antenna on the roof of the building, and pull the fiber down to where we need to go?" And we get the whole building basically to have as good a reception as if you were on the roof. That was really what our original thought was.

ZIERLER: What can you do as a result of having this technology, in office buildings, for example?

LAU: You have a continuous—it gives you mobility. You can take the device, and you can walk outside the building, and you can walk inside the building, and no interruption. In the past, if you're outside the building and you are surfing the internet, you walk inside—or you are talking on the phone—you'd walk into the building, and you got cut off, and you had to start over again. Many experiences of people at the time—when they are driving, they are talking on the phone with someone in the office, and they pull in their underground garage, and you got cut off! That was not a very satisfactory experience. People want to actually have a device that they have in their pocket that will work anywhere they go—outside, inside—and anywhere they go inside the building. Not just to work when you're on the top floor, but if you work in the basement as well. The basement reception was typically extremely poor. That was not a satisfactory user experience. That was the problem that we were trying to fix.

ZIERLER: Being a Berkeley professor in the late 1990s, being involved in technology and communications, what was that like, at the height of the dot-com days, before the bust?

LAU: Of course everybody was talking about starting companies, with the vision of getting rich quick. Of course it didn't quite happen that way. Everybody was very keen in starting new companies, at the time. I think Caltech is probably the same. It's no different. At Berkeley, I had a couple of very good students. They were good technically. One of them was a Caltech graduate, by the way. I recruited him from Caltech after I went to Berkeley. After I came to Berkeley, I said, "I need some good students." So I called up my schoolmate at Caltech, Kerry Vahala. Vahala is now a professor at Caltech. I called him up—"Hey, you got any new students that I can recruit to Berkeley?" He said, "Well, this fellow:" Named Dave Cutrer. I thought I should talk to him, so I made a trip down to Caltech, and actually took Dave Cutrer to lunch, and recruited him. "Hey, come to Berkeley, and work for me." And he did.

ZIERLER: The development of distributed antenna systems, is it basically the same today? In what ways has this technology evolved?

LAU: Things have changed a lot, because that was more than 30 years ago that we did that original thing. In 30 years, technology of course changed a lot. Right now, I think it has evolved to more usage of digital transmission, because the basic premise of the first idea of the distributed antenna system was that you take a radio wave from the outside, and just basically fit the same thing inside the building, so that it makes no difference, so you wouldn't know that you were outside or inside the building. Basically it's just take whatever is outside, as verbatim, and put it inside. That was the original distributed antenna. But now I think that they inject a lot more of the digital technology in there now, so it's really not the same direct modulation of the laser anymore. I think that was probably the biggest change. And also that the high-speed fiber was so prevalent these days that you were able to digitize the entire radio band, and then to transmit a whole band digitally. That was a major difference, a development that happened in the last 20-some years.

ZIERLER: The development of distributed antenna systems for outdoor applications, is that basically the same technology or is that different?

LAU: It's the same idea. Now, the outdoor would be the same thing that—right now it's all the cellular towers that supply the signal for you when you're outdoors. Then of course especially in urban areas, there are a lot of shaded areas that you don't get good reception. Also nobody wants to make ugly cell towers in their backyard. Nowadays, they evolved to basically try to get rid of those, and instead just basically use small antennas that you can mount anywhere, inconspicuously. Like on every light post, on every utility post, you can put an antenna up there. There are fibers everywhere there, so you can pull a fiber and connect them to the antennas. As long as you have the basic technology of transmitting radio wave on fiber. So, they're all connected.

ZIERLER: Tell me about your decision to go emeritus in 2005.

A Research Career Cut Short

LAU: I don't know if I have sent you the article in the IEEE Journal of Microwaves that basically came from an interview like this, like what you and I are doing, with the editor of the journal. It basically told my story, this entire story of my professional career. Did I send you that? No?

ZIERLER: I have that, but I want to hear it in your own words.

LAU: First, the event that really fomented my retirement—now when I first went to academia, when I was a professor at Berkeley, I would think that I enjoyed this job really so much that I will never retire. Actually, it's the truth. Every morning I'd go to work and I said, "I'm really liking this job so much. I think I'll never retire. As long as I'm still able to get in my office." Unfortunately, by early 2000s, when I was still in my 40s, THAT was exactly what I was not able to do. the last paragraph of that paper in IEEE Journal of Microwaves told of an unfortunate surgical event that rendered me wheelchair-bound in 2000/2001. Given that, I really didn't think I would be able to fulfill the full duty of being a professor anymore. Because being a professor is not just giving lectures and talking to students. You have go out and interact with people. You've got talk to funding agencies. You have to go to Washington to talk to the funding agencies. There were other things I wouldn't be able to do, in my present state. So, I thought it was time for me to step back.

ZIERLER: Would you like to talk a little bit about the event, what happened?

LAU: This was what they call the AVM—arteriovenous— a group of artery and veins—arteriovenous malformation. In a normal setting, the arteries supply the blood. Then it branches out into, especially like in the brain, the artery will supply blood, and then it branches out into capillaries, to feed oxygen to different parts of the brain. Then there's also another network of veins that collect all the blood and pump it back through the heart and circulate the blood. In normal circumstances, the artery would go into the organ, and spread out in capillaries, and then the vein would go into an organ, and spread out in capillaries, and through the capillaries, it would first—the capillaries of the artery will supply the oxygen, and then the capillaries of the vein would collect the blood that is depleted of oxygen. The artery that is being used to collect it goes back through the heart. That would be normal.

Now, what I have in my brain is a congenital thing. Because the brain doesn't really grow that much after you are born. Basically all arteries and veins, they were formed, even when you were a fetus. So, it's congenital. Now in my particular situation, this thing called arteriovenous malformation, somehow the arteries and the vein, it doesn't go through the full set of capillaries. So, there was a shunt, in other words, it short-circuited. The blood would go into the brain through the artery, and then it got directly over to the vein, without going through the set of capillaries that supplied oxygen. So that was AVM, arteriovenous malformation, that was in my brain. It was there since my birth. It was supposed to be quite rare, but on the other hand, I know of at least two other people who have had it, at Berkeley, one was the late Berkeley chancellor, Chang Lin Tien, the other was a well known professor in material science and physics, Daniel Chemla. Both underwent brain surgery to resect the AVM, both died shortly after. But many people who had it didn't even know that they had it, it would only be discovered at the autopsy after they died.

I didn't know I had it for the first 50 years of my life, actually for the first 44 years of my life. Everything was normal. You don't know it's there. It's usually not discovered unless you do a brain scan, and one does not usually do brain scans for no particular reason. In my case, I had a seizure one morning while I was still in bed, I was taken to the emergency room, and then they looked at my brain, took a CT of my brain, and they saw this thing right away. The doctor advised that, "Well, first of all, it's not immediately fatal." Now, I have had it all my life, and there was nothing at all unusual about that. He said, "But, on the other hand, going forward, as time goes on, this shunt between the artery and vein in the brain, it could burst at any time, at any unpredictable time. When it bursts, then that's the equivalent of a stroke. Then it could be instant death." So basically that I have this thing, this time bomb in my head, that I don't know when it's going to explode, and every morning I wake up, I don't know whether or not it's going to be my last day. How can I even plan my life that way? So I decided, "Well, I need to get rid of this." That's why I selected the surgical procedure, to take it out.

ZIERLER: Was it in 2005 when you first experienced mobility issues?

LAU: Actually, my surgery was in 2001. Basically right after that, I still remember—the last thing I remember is I actually walked into the hospital for the surgery. And that was the last time I walked. After the surgery, my left side was paralyzed. Now, the surgeon's report says that once he opened up my head, he saw that the AVM already had burst, and so he tried to save my life, in a way. From my perspective, there's a finite chance, a small and finite chance that that thing would burst at any time, as I was told. But what would be the likelihood that I was so fortunate that it just burst at the very moment that a surgeon opened up my head, or was it his opening up my head with a skull saw that caused the thing to burst? Of course, that I will never know. Then even after the initial surgery, the surgical report said there were some infections in the brain that the surgeon had to re-open my brain three more times to clean up the infections. After all of that, basically my left side was—it wasn't paralyzed; I can still move it. I can still move my left hand and leg and fingers. But I just don't have fine motor control anymore. Also my left vision field is also compromised. Now, the left vision field is not the left eye; each of my eyes is still working fine. But my entire left vision field, I have a neglect for that, basically. For example, if I'm sitting at the dinner table, and you put a cup of water on my left side, I couldn't see it. If I turn my head to the left, then I can see it. But basically my peripheral vision on my left side is gone. With that, of course I cannot drive. So, everything together, it's too hard to keep going. Somehow, I still kept going for five years, at Berkeley, before I finally called it quits.

ZIERLER: Perhaps it's difficult to think about, but were there any scientific or engineering projects that were cut short, that you weren't able to complete, as a result of this event?

LAU: Of course that happened right in the middle of the growth phase of LGC after I started it in 1997, so I really wasn't able to put any significant effort into LGC. Even though LGC was in very, very capable hands by then, my three students—John Georges ("G" of LGC) and Dave Cutrer ("C" of LGC), and Simon Yeung, were extremely capable, they basically set the course of LGC going forward together with a growing team growing, that eventually brought LGC to a satisfactory conclusion, despite various missteps by the original cast of business executives brought in by the venture capitalists on the board. Now, scientifically, as far as the work at Berkeley, of course everything stopped. All the work on high-speed lasers and also on further applications of microwave photonics, they all stopped. They stopped instantly, basically.

ZIERLER: What pleasures have you taken in seeing the afterlife of all of your contributions, your engineering achievements?

LAU: I'm not one who is good at adjectives. I can say it is gratifying, but I don't know how else to say it. I'm just gratified I had made a meaningful contribution.

Laser Dynamics in Historical Perspective

ZIERLER: Taking a retrospective look at your achievements, your contributions, let's start with semiconductor laser dynamics. What do we know about semiconductor laser dynamics as a result of what you did?

LAU: Before I worked on it, the semiconductor laser dynamics was formulated and known, for like 10 or 15 years before that time. It ended up with not a very clear indication of how exactly we should build a high-speed laser. My work basically crystallizes that into just a few very simple parameters that you can directly control by material and structure. Basically, it makes things simple, in a way. It makes it simple. My work basically allows to you say, well, if you increase this, decrease that, then you get a high-speed laser. Whereas before, you have like a half dozen parameters kind of intertwined, and so it's not clear exactly what you need to do to build a high-speed laser. I think that would be my biggest achievement. Before me, there was no high-speed laser that could be modulated with high fidelity at above 2 or 3 GHz, and based on my formulation of laser dynamics, 25GHz lasers are now a commercial reality, these lasers are the foundation that launched today's Tb/s internet backbone. I do realize that unless you are doing something very fundamental, but if you are actually building products that serve people, all technologies will be superseded by something better at some point,

The other thing is about fidelity. Having a high-speed laser is one thing, but exactly how well can you replicate the electrical signal at the optical end? Because when you transmit microwave, you don't want distortions. You want as minimum distortion as possible. That, of course, is also important. Another aspect of my work that it was using the—I think I mentioned it in my PowerPoint—is nuclear diagnostics, the nuclear test people. They need that because a nuclear test is by definition a single-shot event. It's a boom, and then it's gone; you cannot repeat it. In that one moment, you need to capture whatever happened at the implosion site and then transmit it to whatever recording equipment that you might have. That demands high speed and high fidelity as well. They couldn't have gotten all the data of the nuclear tests without this kind of device. In the beginning, actually, in the first few years of ORTEL, high-speed lasers were fine, and people knew that eventually they were going to need it. But on the other hand, the internet wasn't there yet. It was in the early 1980s, and the high-speed internet wasn't there until a decade later. So in the early years of ORTEL, we basically survives, actually doing fairly well, because of the nuclear testing community, that they use our devices and they use our fiber links to capture data. The nuclear test is a good customer, because they bought a lot of lasers from us, and then they took it to Nevada, and just blew it up. Just like that. Every device we sold them, they would just go vaporize it in the Nevada desert, and they'd come back and buy more! Talk about repeating customers!

ZIERLER: [laughs]

LAU: That was in the early to mid 1980s. By the late 1980s, the nuclear tests were winding down. Glasnost was happening in Russia. Then also the Comprehensive nuclear Test Ban Treaty was just about to be signed. So we knew that that nuclear test activities wasn't going to last forever. Fortuitously, just about that time (mid-1980s) one of our marketing managers took our product to the Wester Cable Show and caught the attention of a major cable infrastructure vendor General Instrument, they wanted to use our lasers to transmit cable TV signals. The effort to produce lasers for cable TV v application was spearheaded by another of Yariv's students, actually my schoolmate at Caltech, by the name of Hank Blauvelt, who joined ORTEL at the time. said, "Hey, the cable TV industry is interested in our device, in our product," actually, my reaction at first was lukewarm. Because at that time, cable TV wasn't a big business. Like, who would be watching cable TV? Just a couple of old ladies sitting in an afternoon watching a soap opera; that was it. At least that was the impression of the state of cable TV at the time. So I didn't think that it was anything big.

Of course, everything changed when the internet came out in the 1990s, and you want to deliver high-speed internet into the home, so you have to look at all the wires that go into a typical home that you can possibly use to transmit CATV signals. Well, there are the utility wires. But that's a little bit too tough to transmit high-speed data. Now, there's a telephone wire. That was being used by DSL, the ADSL. That was an ingenious scheme of how to send megabits of data through a lousy twisted-pair telephone cable. But it has its limits. The other major conduit into a typical home is the cable TV. So, when the internet came about, and you want a high-speed conduit into homes that's existing, cable would be the one. Now, one thing is that with this experience I learned the importance of respecting legacy infrastructure. Whatever is existing. Use whatever is existing as much as possible. Because putting in new cables is always very expensive. It's disrupting and it's expensive. So whatever exists, you should use as much as you can.

The success of DSL was that you use existing wirings. Now, the cable was another thing that was existing, so you could use the existing cable infrastructure for a high-speed internet connection, and cable is a MUCH superior high speed medium than twisted pair. Even though it is not the best medium available, but its already there, enables you to roll out the service quickly. But eventually of course everything got replaced by the more advanced version, which is fiber. Eventually you got fibers at the home and fibers at the desktop, and transmit everything digitally. But I would say that for digital transmission, fiber digital transmission, I still have the last laugh. Because you still need high-speed lasers the fundamental principles of which I originally developed in the 1980s! So I have the last laugh!

ZIERLER: In surveying the infrastructure, the hybrid fiber coax infrastructure that exists today, what do you see as your key contributions to building that infrastructure?

LAU: In addition to ORTEL's lasers, you also need high power, externally modulated, high-fidelity fiberoptic transmission lines that feed the long reach trunk lines of that that infrastructure. ORTEL's lasers feed the short reach distribution network feeding the hubs to residential neighborhoods where coaxial cables complete the last mile to homes and premises The hybrid fiber coax—the fiber part of the HFC, of the hybrid fiber coax, together with my colleagues at ORTEL, I made a contribution to making that happen.

ZIERLER: As you survey what has been possible with either the Deep Space Network or planetary missions, or accelerator physics, what gives you the most satisfaction in contributing to fundamental research?

LAU: Every time I heard about what people can do with radio telescopes, like observing the first black hole, every time I see a scientific discovery using radio telescopes, I would think, "Well, I played a part in enabling that." Also every time I heard that JPL would accomplish a successful mission somewhere, I would still think that, "Well, I played a part in that, too," to enable that happening.

ZIERLER: To circle back to an earlier question about what Caltech has given you in its education, have you been an active alumnus over the years? Have you been involved? Have you stayed in touch with Caltech?

LAU: I would say that I can be accused of not being a very active alumnus. In my active years, of course, that I was still busy running around and doing research and doing all these startups, I still stayed in close touch with Yariv. I think with Caltech, I mainly stayed in touch through the people who I've worked with, like Yariv and Kerry Vahala. Those, I stayed in very close touch with. But as far as Caltech at large, I was asked to serve on the visiting committee a couple of times. I think the first was when President Thomas Everhart was still there, I served one. Then I served again—Everhart was president in the late 1990s. In 2000, I came again for another visiting committee meeting when Caltech had a new president after Everhart left, that was the last time I served.

ZIERLER: Which one? After who? After Everhart?

LAU: After Everhart, yes.

ZIERLER: David Baltimore.

LAU: Baltimore, exactly. When Baltimore was president, I came down one time for the visiting committee of the Engineering and Applied Science Division. The first time I came, in the late 1990s, I was still walking as a normal person, so it was still a "normal" visit on my part. By the time Baltimore was president, I was already in a wheelchair. So I came down in a wheelchair, actually, that one time, to serve on the visiting committee.

ZIERLER: Finally, for my last question—either from our discussion or later this month when you talk to Sandra Loh as part of the DAA ceremony, what do you think is the main takeaway? For people who want to study your career and your life and want to learn from what you achieved, what are some of the main lessons that people should take away, as you reflect on your achievements?

LAU: I would say that I would always chase applications as the primary criterion of deciding what you do. There are people, especially those in basic science, but even in art, as I mentioned before, my high school art teacher said that, well, you start with just playing around with something. You don't have to have a definitive goal of an end product before you start something. Just play around with ideas and pieces will fall in place, and then you form a vision of will see what great things can come out of these seemingly random things. I think Feynman even said that—at one point, he said, he didn't know what good idea to do, and he was just playing around with things, and then things followed, and then you just have to notice that something is useful, and just grab it. That's one approach. But my thinking and approach tend to be that when you think of something, before you devote major resources into it, you should first figure out what is the potential use for that, before you launch into it. So basically have a good sense of applications in mind, front and foremost.

ZIERLER: Earlier in our conversation, you expressed wonderment why you would be considered a recipient of the DAA in light of all the others who came, yet I think our conversation explains exactly why you were named a Distinguished Alumnus. I'd like to thank you so much for spending this time with me. It has been a lot of fun, very meaningful, and congratulations, once again. Thank you so much.

LAU: Thank you very much for spending the time, too.

[END]