Oral-History:Michiyuki Uenohara
About Michiyuki Uenohara
Michiyuki Ueonhara is a communications engineer known for his work in semiconductors at Bell Labs. He received his bachelor's degree in electrical engineering from Nihon University in 1947, and then went to the United States for further research, receiving his masters' and his Ph.D. degrees in electrical engineering from Ohio State University. He returned to Japan in 1956 to receive a Japanese Doctor of Engineering degree from Tohoku University, and then returned to the United States in 1957 to work in Bell Labs' microwave electron tube laboratories. After demonstrating low-noise capability for the parametric amplifier within three weeks of his arrival at Bell, Uenohara switched to Bell's semiconductor group in the electron tube laboratory. The interview begins with an overview of Uenohara's early interest in science and engineering and treats the complicated circumstances of his education during World War II, including his military training and his education at Nihon University.
After discussing his work at Nihon, including his work as Prof. Okabe's research assistant and the assistantship he held at Nihon after his graduation, Uenohara discusses the circumstances of his move to the United States and his research at the electron tube laboratory established by Heil at Ohio State University. He describes his electron tube work at Ohio State, mentioning Bell Labs' recruiting efforts and the U.S. Air Force contracts which financed his Ph.D. work. He describes his experience presenting his research report at the electron tube research conference at Stanford. After discussing his return to Japan in 1956, the Doctor of Engineering degree from Tohoku and his lectureship at Nihon University, Uenohara discusses his arrival at Bell Labs in 1957 to work in the microwave electron tube laboratories, his work on the parametric amplifier, and his consequent switch to Bell's semiconductor group. The interview concludes abruptly with Uenohara's description of this switch.
About the Interview
MICHIYUKI UENOHARA: An Interview Conducted by William Aspray, Center for the History of Electrical Engineering, May 16, 1994
Interview #198 for the, Center for the History of Electrical Engineering, The Institute of Electrical and Electronics Engineers, Inc.
Copyright Statement
This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.
Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, IEEE History Center, 445 Hoes Lane, Piscataway, NJ 08854 USA or ieee-history@ieee.org. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.
It is recommended that this oral history be cited as follows:
Michiyuki Uenohara, an oral history conducted in 1994 by William Aspray, IEEE History Center, Piscataway, NJ, USA.
Interview
Interview: Uenohara, Michiyuki
Interviewer: William Aspray
Date: 16th May 1994
Place: Tokyo, NEC Head Office
Background and Early Education
Aspray:
This is an interview with Dr. Uenohara at NEC corporate headquarters in Tokyo. Dr. Uenohara, I was hoping that you could begin by telling us about your early life and career: when you were born, where you were educated, what your parents did, and so on.
Uenohara:
I was born on September 5th, 1925, in Kagoshima which is in the South of Kyushu Island. My father died when I was six months old. He was a primary school teacher. I was the youngest of nine children. So my mother raised nine children. She had an extremely hard time and we didn't have enough family funds to provide for higher education. Most of my brothers and sisters went to teachers college, what you would call normal school.
Aspray:
Yes, to train them to be school teachers.
Uenohara:
Yes, because tuition was free, and they also received a small stipend. That way they helped my mother, by not burdening her financially. After they finished school they supported the younger brothers and sisters. I was raised this way. My father was a teacher, and almost all of my brothers and sisters were teachers. So even though my family was extremely poor, I was in an extremely good educational environment. My sister and brothers taught in the town where I was born. After school, many of their friends, who were teachers, came to my house and engaged in very interesting conversation. I was still very young, but I sat among them and listened to their conversation.
My family has a background strong in science and mathematics, so my brothers and sisters were strong in science and mathematics. My family were farmers, but my great-great grandfather was strong in mathematics. He was appointed mathematics teacher to the Satsuma lord during the period before the Meiji Restoration. So he was allowed to bear the sword, even though he was a farmer. Because he became a mathematics teacher. From this story, you can understand my basic talent. I was very strong in mathematics and science from childhood. I liked to solve mathematical problems, and I also liked to fix mechanical gadgets. My family was so poor that, even to send a student to normal school, we needed extra funds. So to raise money my mother sold a part of our house lot to a man who repaired clocks and watches. Even before I entered the primary school, I was usually left alone at home. My mother went to farm in the fields. She also sold vegetables and fruit at the market, late in the afternoon, so she came home late. So I was left alone at home. I often visited neighbors' stores to spend my time. I watched electric equipment and bicycles being fixed, I saw how clothes were washed, how sewing machines operated, and so on. I also sat next to the watchmaker and watched how he fixed the clocks. He made the parts by hand, using a small desk lathe. I quickly learned how to fix watches.
Aspray:
You could fix watches as a boy?
Uenohara:
Right, I can fix almost any kind of watch or clock. So this way, I learned techniques from the neighboring stores. I also learned scientific and mathematical knowledge from my brothers and teachers. That's why I say I was born an engineer.
Aspray:
Yes. What did you think you would be when you were growing up? What profession did you think you would have?
Uenohara:
Well, I wanted to be a scientist, a great inventor! It's just that I couldn't accomplish my childhood dream. But I think I have demonstrated that I am a born engineer.
Aspray:
Did you have to make choices at various points during your education about which career path you would take?
Cadet School & Army Air Force Academy
Uenohara:
Yes. In contrast to my dreams, I had to switch my career because of many circumstantial changes. After primary school I wanted to enter a prestigious middle school, then go to high school, then enter engineering college in order to become a researcher and a great scientist. But our financial situation prevented this. However, my brothers' and sister's support helped me to enter this middle school. But I knew I was giving a financial burden to my family. So after two years in middle school I decided to enter the military cadet school.
Aspray:
What age would you have been at that time?
Uenohara:
At that time, I was fourteen years old. Of course, I received a great education, even though it was military cadet school. We had highly qualified teachers. Eventually most of them became college professors. After finishing cadet school I went to the military academy, then I went to the military flying academy. At that time we didn't have an Air Force in Japan, only the Army and Navy. So I was in the Army in cadet school. They had two schools, one for the ordinary army, the other for the Army Air Force. I went to the Army Air Force Academy.
Aspray:
What were you taught there?
Uenohara:
At the beginning they gave us such a general education one could either be a pilot or an engineer. Airplane engineers were communication engineers. I wanted to be an engineer, even though I was an Army military officer. At that time they had a fellowship system, where excellent officers were sent to the university for special education, and also to participate in university research. I wanted to take that course. So I volunteered to select airplane maintenance engineering, but after the pilot test I received an excellent score as a pilot.
My academy teacher asked me, "Having such a such a high aptitude as a pilot and since most of the cadets want to be pilots, why did you choose a ground job?" I told him that I wanted to be an engineer from childhood. I thought I could contribute the most by knowing the problems of military airplanes, and I could improve those problems, that's why I wanted to be a maintenance engineer. Then he asked me, "Are you afraid of dying?" The risk is much greater for airplane pilots than the ground forces. I said, "No, not that." But he insisted that I was very timid. So I decided to become a fighter-plane pilot.
Aspray:
Of all the different kinds of pilots the fighter pilots are the ones who have the highest risk?
Uenohara:
That's right, yes.
Aspray:
Why did you choose that? Just to show him that you weren't afraid?
Uenohara:
Right. But also, you see, I could communicate with the maintenance soldier, one on one. I could know myself the merit of the airplane. That is also why I chose to be a fighter pilot. But I had to stray from my young dreams.
Aspray:
The war was in progress by this time, wasn't it?
Uenohara:
Yes. Two weeks before graduation, the war ended. I was so relieved! I was not a good army officer candidate!
When I was in the Army flying academy, the Japanese military forces were facing very difficult times, losing so much military strength to the Americans with their strong electronic equipment. Also the ability of the American radars surprised the Japanese officers so much. When all the academy graduates came back from the war front, they visited the academy. After supper everyone on the campus assembled and listened to their story. They told us the Japanese armies were facing an extremely difficult time because of a technological handicap against the American forces. At that time, most of the army officers told us that we could win if we kept our spirit.
Aspray:
I see, if you had the will, and you had the spirit, you could win the war.
Uenohara:
They told us that we could overcome the technological handicap technology. But I thought we wouldn't be able to overcome the technological handicap just by will and spirit. Even then I was thinking how we could improve the technology in a short time, but it was hopeless. When the war ended, at that time I was in Manchuria, where our forces were training. We couldn't fly in Japan because of the frequent air raids. We escaped to Manchuria and then did training. I learned that the war had ended while I was in Manchuria. During the repatriations back to Japan, I thought of how I could contribute to the rehabilitation of the Japanese economy. I decided the only way I could contribute was to become an electronic engineer.
Aspray:
That meant that you had to go back to university then?
Nihon U. & Microwave Research
Uenohara:
Right. So I entered the Nihon University, the next year, in 1946. That was the first year I could start a program.
Aspray:
How did you choose to go there, rather than some other school?
Uenohara:
Well, I didn't know too much about the Japanese university system. Of course, I knew about the famous Imperial universities, because I had heard so much about their activities. But I didn't have much information about what other universities existed. Also, I couldn't get any financial support from my family to study in the university, so I had to work. First I picked the University of Tokyo because the tuition was the lowest! But my foreign language was Russian, because Russia was the first enemy of the Japanese army, so in military cadet school I studied only Russian. I only had two years of English lessons at middle school, which was almost forgotten. I quickly prepared for the entrance examination, even though I had to work. I didn't have much time to prepare for the entrance exams. I had much confidence in my ability in the mathematics and science parts, but not in the foreign language. Later I learned that Russian is very close to English, after I went to the United States, but of course for the Japanese, English is quite different from Russian.
So at first I discovered which university accepted Russian as a foreign language. Only Waseda University did, but it was not an engineering school, it was a school of literature. No engineering schools accepted Russian as a foreign language. I had a challenge without too much knowledge of English. Also I didn't study any German at the time, and they had two foreign language tests, English and German. No hope! But I first took the entrance examinations at the University of Tokyo. I thought I did pretty well in mathematics and science, but on the German test I couldn't answer anything. You had to translate Japanese into German, so I answered in Russian — I translated it into Russian. If the University of Tokyo accepted that, I could recognize how great University of Tokyo might be. If they didn't accept it, I had no thought of entering anyway. Well, I failed. Then I looked around, and I found that only Nihon University had not yet finished its entrance exams, so I applied. Fortunately, I was accepted.
Aspray:
Where is it located?
Uenohara:
In Tokyo, very near to the University of Tokyo.
Aspray:
What was it known for, what was its specialty?
Uenohara:
After the war there were only a few private universities which had engineering schools. Waseda and Nihon universities, I believe only those two. And Tokyo. I think there were also a few colleges. But not universities.
Aspray:
I see. When you apply to enter a school and take the entrance exams, do you tell them in advance what course of study you want to take?
Uenohara:
Yes. I applied to the school's college of electrical engineering.
Aspray:
At that time, was the electrical engineering study mainly power and communications?
Uenohara:
Power and communications, yes. Of course there were no semiconductors, transistors, or computers. At the end of my freshman year, a new professor, Professor Okabe, joined the faculty. He happened to be a microwave tube engineer. That was again a big switch in my career. Professor Okabe had a strong impact on me. I liked his lectures, so I often asked him special questions and visited his laboratory. Soon I became his assistant. I helped him with his research, and he taught me so many things, the basic way of thinking.
Aspray:
Was the general course of study a strong one at the university? Did you get good preparation in your engineering basics and your science?
Uenohara:
No. This was right after the war, and the professors and the students had to find food to live!
Aspray:
Very difficult!
Uenohara:
Right. I didn't get a normal education. But that was very fortunate for me. I always tell current students, "You are very unfortunate, you have to attend classes more than 70% of the year, otherwise you cannot get a grade. Even though you don't like the professor, you have to sit in the class!" In my time, if I didn't like the professor, I didn't need to attend the class. I only needed to take a final examination, and then I passed and got the grade. So I studied the work I was most interested in.
Aspray:
Were there many other professors in other universities in Japan at this time who were teaching microwaves?
Uenohara:
Not many. There were a few. Of course, right after the war there was research on microwaves, but it was prohibited because of the eventual connection to military technology. But in a few years that restriction was removed, so we could do research. Then Japan had to reconstruct a nationwide communication network. Of course, that was as important for the American forces as it was for communications purposes. So the Allied forces applied strong pressure to the Japanese government to quickly reconstruct a nationwide communication infrastructure. For that reason, many professors who were interested in microwaves thought that microwaves would be a very important technology.
Aspray:
Because of so many islands, and mountain ranges —
Uenohara:
And mountains. So for Japan microwave communications is the most effective. Laying a cable is very expensive.
Aspray:
Yes.
Uenohara:
A few of the professors started the microwave research committee, a study group. My professor, Professor Okabe joined that committee. Even though I was a college student, I accompanied my professor and sat in those meetings. So I happened to know many professors in that committee, even though I was still a student.
Aspray:
I see. Were you a good student? Did you graduate with high grades from the university?
Uenohara:
Even though I did not attend many classes, I received honors.
Aspray:
Very nice.
Uenohara:
My grades happened to be good enough, even though I only took the final exam.
Aspray:
What did you plan to do when you finished college?
Uenohara:
First I thought of joining a company because of financial reasons. But job opportunities were so scarce. You had to do extensive visit to the company. Also, professors had to help with connections to these special managers. But Professor Okabe didn't help me. He said, "Don't worry." I asked him what company I could work for as a student. Professor Okabe said, "Don't worry, you don't need to spend precious time job hunting." So I became an assistant of the college.
Aspray:
You were a paid employee?
Uenohara:
Yes.
Aspray:
Did that mean that you did some teaching? Or you worked in the laboratory?
Uenohara:
Mostly it was research, and I helped students do the lab course.
Aspray:
You did that job for how long?
Uenohara:
Three years.
Aspray:
Did you feel that you were continuing to learn while doing that job?
Solid State Microwave Tube
Uenohara:
Yes, I learned a lot. We had special seminars in the laboratories, so we had very advanced knowledge. But the problem was, at that time, the university laboratory did not have adequate facilities. Even today, Japanese professors claim they don't have enough facilities.
Aspray:
But things were especially bad then?
Uenohara:
Especially bad. My research subject was the microwave tubes. You need high-precision equipment to assemble microwave tubes. We didn't have such equipment. We were fortunate enough, because of professor Okabe's good connections with the major electronic companies in Japan, to receive some support from these companies. But still it was not enough to advance our research. We considered how we could accomplish the necessary performance without using precision mechanisms. We started to use the concept of dynamic negative resistance for microwaves so that we could amplify the microwaves. I spent two years in Nihon University working on this concept. Eventually the dynamic negative resistance helped my work on the parametric amplifier. So for me, it was very straight progression.
But still, I wasn't quite satisfied. I was constantly thinking how you could generate, or amplify microwaves, or even millimeter waves, without having a precision mechanism. One day I was reading Physical Review, in the CIA library, in Hibiya. The only thing we could read were American journals at the time. I happened to find microwave spectroscopy work, at the very beginning of microwave spectroscopy, to study the molecular structures of matter. I found out that it was utilizing very sharp, microwave-absorbing characteristics of materials to analyze molecular structure. I thought that if these special materials absorb a specific spectrum of the microwave, if we could do some trick, we might be able to use material to generate similar waves. Professor Okabe taught me the relationship between linear accelerator and amplifier — that is, microwave and electron beam interaction. If the electron beam absorbs energy from a microwave, it becomes a linear accelerator. If the kinetic energy of the electron beams is transferred to the microwave, it becomes an amplifier. Also he told me that it was very similar to the relationship between motors and generators. So that's the basic way of thinking of energy interaction.
It strongly impressed me, and remained in my thinking. I read that these special materials absorb microwaves very sharply. So if we could devise some trick, we could change the relationship. Then these materials could emit microwaves and would amplify the weak signal. I was so excited. I returned to the laboratory and asked Professor Okabe, "Could that be possible?" He said that he didn't have enough knowledge in solid state physics to tell if it was possible or not. He advised me to knock on the door of famous physics professors, solid state physics professors. So I knocked. Everywhere I was turned back. "Stupid idiot!" So I decided that if I studied in the United States, with their advanced electronics technology, some professors might be doing the kind of research which I had dreamed of. That was really the next career switch, to move from the Japanese university to the American university.
Aspray:
You said that you had access to the American literature on microwaves. What kinds of things were available to you?
Uenohara:
Major journals were available.
Aspray:
Did you have all of the publications from the Radiation Laboratory made available to you at that time?
Uenohara:
Not at that time. At that time they were not published yet. Of course, that became the Bible afterwards. But at that time the MIT series was not available.
Aspray:
Once you had decided to go to study in the United States, what did your professor in Nihon University think of this? Was he supportive?
Uenohara:
Yes. He helped me by recommending me to the professors whom he knew. But of course definitely limited numbers. The professors did not have enough openings. Again I had to go to the CIA Library to look through the small booklet on study abroad. I also surveyed all the journals, selecting the authors of the familiar literature. I checked in this booklet on study abroad to see whether his university had fellowships or research assistantship that could be available for a foreign student. Then I wrote letters.
Ohio State
Aspray:
I understand you went to Ohio State?
Uenohara:
Yes.
Aspray:
Did you seriously consider other schools also?
Uenohara:
Yes. Ohio State was not my first choice, but they gave me a fellowship.
Aspray:
Who were the professors there that were interested in your field?
Uenohara:
Professor E.M. Boone was my advisor who offered me a job. But Professor Heil, the very famous microwave tube man, who came from Germany, established the electron tube laboratory at Ohio State. When I applied he was still there, but by the time I joined, he was not there; he had moved.
Aspray:
What did you work on? What were your problems?
Uenohara:
Professor Boone explained the kinds of research that were going on in his laboratory, then he asked me which one I would like to join. But I was not quite impressed, so I talked to him about my ideas of the solid state and the microwave generation. He said no one in the university would be able to help me. I then explained to him what I was doing at Nihon University, and what kind of new ideas I had with the microwave tubes. Then he said, "Why don't you continue your work in my laboratory?" So I started my work immediately.
Aspray:
Did he have the background in solid-state physics to support you?
Uenohara:
No. He was a microwave man; his specialty was in the tube area. But he was interested in transistors. This was right after the transistor was invented. So he was studying transistor circuitry, but he didn't have a solid-state physics background.
Aspray:
How did you do on your own with your research project?
Uenohara:
I quickly designed the tube and asked the machine shop to make the tube components. This laboratory had extremely good facilities, and they had a special technician to assemble these very complicated tubes. But my tube was so special! They could not assemble it. I told them I could fix any kind of watch, and the boss of the technicians looked down at me and said, "If you have this competence, why don't you try to do it yourself?" I said, "Okay, if you give me permission to use these facilities, I'm glad to try." And I succeeded. Because I designed it, you see.
Aspray:
So you actually got into the shop and did all the work yourself?
Uenohara:
Right. I began to be a very good friend of the machinist and the tube assemblers, and the tube component processing technicians. Of course, you had to de-gas all the parts, otherwise the tube wouldn't last long enough.
Aspray:
Could you explain what the really difficult construction problem was there?
Uenohara:
My tube was producing pendulum motion: electrons, simultaneously the rhythm of the cavity was generating microwaves. The cavity had a very narrow slot where it interlocked the electron beam and the microwave field. The static electric field distribution within this interacting space would be parabolic, so the electron beam does simple harmonic motion. To make the first tube design simple, I made long, horizontally extended structures, which in cross-section were identical, in order to make the electron beam density sufficient to have enough energy to interact with the microwave. The resonant cavity is cylindrical. That means the cathode has to be linear, a very narrow strip cathode. They couldn't attach this cathode. So I used my skills at using tweezers and the microscope and welder.
Aspray:
I see. And the result worked very well?
Uenohara:
Yes, the first model worked. That often happens, that the first model will work. But then usually the second won't work. Second, third, fourth, and fifth one won't work. At that time that was normal, but my tubes worked, one after another. I wanted to extend my stay, because in only one year's stay I couldn't accomplish too much.
Aspray:
Yes.
Uenohara:
- Audio File
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I wanted to stay at least two years. So I quickly wrote a report and submitted it to my advisor. He submitted my paper to the electron tube research conference, without notifying me. After they accepted my paper, he notified me. That was the next jump. Because in less than one year I had this great chance to give my paper at what at that time was the biggest research conference. It was extremely difficult to be accepted. I was so scared to give a presentation by myself, because my English was terrible. So I asked Professor Boone to present my paper because my English was so poor. I felt I would waste the audience's very important time. Professor Boone said to me, "This paper is yours, not mine. You are the only author." He also told me that he knew many Europeans with terrible accents who were hard to understand. He said, "Don't worry. Just present it by yourself." So I did. Of course I practiced and practiced, almost completely memorizing my presentation.
The research conference was held at Stanford University. No digest was issued. No tape recorders or cameras were allowed. This was a completely front-end research conference. So I couldn't find what kind of researchers could present a paper at that conference, or who would be attending the conference. When I registered I received a list of participants. There was a famous name! I was so shocked I started trembling! Anyway, I gave my talk; that was no problem. But when the question-and-answer session started, I could not understand the questions. The first to ask a question was Professor Heil, the very famous microwave man — he was almost a God to us. He started talking with this heavy German accent, and I didn't understand whether he was telling me his story, or whether he was commenting, or asking me a question. But I had to say something. Professor Boone and I had sat down before I left for the conference, and we had anticipated the possible questions. Then he drafted the answers, and I memorized all of them! I picked up the most important questions that we had thought of. I quickly squawked that answer. I didn't know if that was the question asked or not, but that happened to be the answer! I was fortunate. When the intermission came, many people surrounded me and congratulated me, and I also received many questions. Anyway, I thought I didn't do so badly.
Then I had about a week's vacation before I returned to my laboratory. I found a pile of letters awaiting me on my desk. There were a few letters from Bell Laboratories. I found out that many of the members who surrounded me at the intermission were Bell Laboratories people. They asked me to join Bell Laboratories. They offered a much better opportunity. But I was at the university on an exchange-visitor's visa. That visa doesn't allow one to work; I could only get remuneration from the university. Also I had to be outside of the United States at least two years before I re-entered the United States. So I told them, because of my circumstances, I wouldn't be able to accept their offer, unfortunately.
Aspray:
Was this a disappointment to you?
Uenohara:
No, I was thinking of returning to Japan eventually, because my contract with the Nihon University was still in force. I had to get permission from Nihon University in order to join Bell Laboratories. Also, a few months later I received a big contract from the U.S. Air Force for my research. Again, that was another good result of this presentation.
Aspray:
I see, so somebody from the Air Force had learned about your work?
Uenohara:
Right. That contract provided the funds to guarantee my stay at the university, to finish my Ph.D.
Aspray:
It was possible as a Japanese national to have a U.S. military contract?
Uenohara:
This was actually basic research, so there was no specific military purpose. Just generating millimeter waves. Pure, basic research.
Aspray:
Was this the basis for your Ph.D. work?
Uenohara:
Yes, my masters and Ph.D.
Aspray:
I see. In the rest of the time that you were in Ohio State, how did you develop your ideas? What were the basic things that you did to improve upon your original result?
Uenohara:
Most of the time, at Ohio State, I fulfilled the responsibility for this Air Force contract, so I improved the performance and increased the frequency of generation. I also provided sufficient theoretical background for my tubes. That was enough for my Ph.D. Then for the last years of my Ph.D. I received another Air Force contract, to study the future possibilities for microwave tube innovations. I concluded that there wouldn't be any revolutionary innovation, only evolutionary improvement. So I decided, this is the time to switch.
Aspray:
Do you know what use, if any, the Air Force put to your research?
Uenohara:
I don't think any. They just helped my Ph.D. work. Also two other students.
Aspray:
So you were coming close to finishing your degree at Ohio State. What were you thinking about doing then? Going back to Japan?
Bell Labs Offer
Uenohara:
Well, at least twice every year Bell Labs people visited my laboratory — constantly.
Aspray:
I see. They didn't give up easily?
Uenohara:
No, they didn't. In early 1952, a student left the electron tube laboratory at Ohio State after finishing his Ph.D. and joined Bell Laboratories. He switched to transistors. He represented Bell Laboratories, and asked me to join. He told me that I didn't need to make up my mind immediately, but at least I should visit Bell Laboratories and see what kind of place it was. So I agreed. I visited Bell Laboratories in Murray Hill, New Jersey, in March. I finished my Ph.D. in August. I thought it was just to visit the laboratory and look around. When I arrived at the Murray Hill laboratory I found out that I had to give a one-hour talk in front of Bell Laboratories people. I hadn't prepared anything for that because my friend hadn't told me! "Just come over," he said. Stepping into that lecture hall I found out that half of the people were from the microwave tube area, and half of them were from the transistor area, semiconductor area. I didn't know many people in the semiconductor area, but I knew quite a few researchers in microwaves. Also, I had one year's study in the future of microwave tubes.
So I quickly devised my strategy. I thought I should take a positive action rather than passive. The passive would mean to simply step up at the front table and give my Ph.D. thesis as a lecture. I stepped up, exchanged greetings, and then immediately I asked the question: "Will there be any great research opportunities in microwave tubes in the future?" The people from the semiconductor group, when they heard my question, started attacking the microwave people. Then the microwave people battled back. They discussed the question among themselves! When they finally realized what had happened, it was about ten minutes before the end of the session! So I quickly reviewed my thesis. I passed my first test!
Aspray:
Did you like what you had seen at Bell Labs?
Uenohara:
Oh yes. I had three days to visit. They even took me to the Holmdel Laboratories. At that time it was a farmhouse. Presently they have a huge, big modern building, but at that time it was a simple farmhouse. They were doing millimeter wave research there. The microwave tube people offered me many attractive opportunities.
Aspray:
So did you then take a position with them?
Uenohara:
Well, when I left the laboratory, I didn't say anything about my choice. I just thanked them. I didn't say that I would join. But when I returned to Ohio State, I received two offers — from the semiconductor research division and the microwave electron tube development division. I had to make a choice. Of course, I wanted to join semiconductors because I wanted to switch. But I didn't have any background in solid state, even though I had the idea, but not enough basic background. Nor did I have any research experience. I had experience in microwave tubes and the microwave area. I asked my friends for advice. They emphasized that Bell Laboratories semiconductor research division had top-notch physicists from all over the world. How I could compete with such top scientists? Also, my English was still terrible. Without having excellent language skills, how could I debate with them? It might be better if I joined the microwave tube area first, where I had the strongest capability and background, then switch to semiconductors afterwards. Still I would be able to make a contribution. I thought that's a good reason. I accepted the offer from the microwave electron tube laboratories.
Aspray:
And you joined them in 1957?
Uenohara:
1957, yes. I had to return to Japan to change my visa.
Aspray:
I notice that you've also received another degree in Japan. How did that happen?
Uenohara:
Right from Tohoku University. While I was back in Japan, Professor Koike of Tohoku University told me that an American Ph.D. alone wasn't good enough in Japan. He said I should have a Japanese Doctor of Engineering degree. Professor Koike said that if I submitted a thesis, he would be glad to help me receive a doctoral degree. I told him I didn't have enough time to produce another thesis. He said that the same thesis would be fine, if I slightly changed the acknowledgement. Japanese universities are very flexible in that regard.
Aspray:
I see. So you didn't do any new research at all. Did you have to write it up again in a different way?
Uenohara:
No, at that stage it was in English. I added several of the professors' names in the acknowledgement.
Aspray:
I see. And how long were you back in Japan before you returned to Bell Labs?
Uenohara:
Let's see, I returned to Japan at the end of September 1956. I returned to Bell Laboratories at the end of October 1957. So I was there about thirteen months.
Aspray:
Were you at the university all this time?
Uenohara:
Yes. When I accepted the offer from Bell Laboratories, they quickly wrote a letter to the university headquarters, indicating that they wanted to hire me. The university was greatly surprised. They even got mad at me. They sent me a telegram asking me to return immediately to Japan.
Because I didn't tell them, the university asked me to return immediately. That was before my submission of my Ph.D. thesis. I couldn't return without submitting my Ph.D. and finishing the final oral examination. So I ignored them! After commencement, I returned by boat. At the Yokohama harbor a car from the university was waiting for me — to kidnap me! Then a friend of mine came to see me. He told me not to say anything. I wouldn't go back to Bell Laboratories at this time. My friend told me that if the university asked me whether I would stay in the university or not, to just say I would stay. But don't say anything about time. Just say, "Yes." That meant I would not be committed to stay for long. If I just stayed one month, I wouldn't violate my word. So I became a lecturer. I lectured for about one year at the university and did research. My elder brother was assistant professor at the time, at Nihon University. He was working on micro-plasma physics, so we worked together.
He was two years older than me. He was a graduate of the military academy, and he was an officer at the end of the war. He was a prisoner at Singapore. He came back two years later, so he started studying later than I, and I taught him! The younger brother taught his elder brother.
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Aspray:
It's quite clear we're not going to finish today. But why don't we start talking about your career at Bell Labs, if you'll tell me what you did there?
Uenohara:
In order to accept this offer from the electron tube laboratory, we agreed that Bell Laboratory would accept my request. That meant that they opened new research, which I recommended. An extension of my past research was my new proposal. Then after 1957, when I joined Bell Laboratories, I found out that three research teams which I was carrying in the past were already working in the Bell Laboratories. They asked me to lead one of those research groups, but I did not. They already had capable people working in them. I wanted to start anew. We had discussions. Then the parametric amplifiers study came out. Both theoretical work, and a very impractical experiment was already done, but not a very factual one to start. It was not a clear experimental result.
Aspray:
Can you expand on this story? Go back and tell me a little about the history of the parametric amplifier.
Uenohara:
The first evidence of the parametric amplifier was observed at MIT Radiation Laboratory during the war when they experimented with microwave receivers using semiconductor diodes. They found a peculiar effect, some sort of amplification, but terribly noisy, of course. Because it was a peculiar effect, they ignored it. Then two men named Manley and Rowe did the theoretical work on the multi-frequency energy conversion. The theoretical result suggested there is a clear amplification mode. Then many microwave people started looking into the possibility of parametric amplification. In the electron tube laboratory there was a big team studying the low-noise microwave receiver for the long-range radar receiver application. They had a huge fund from the Air Force, and they developed a variety of low-noise tubes, but they couldn't achieve the target of 6db noise figure. So I thought there was no experimental evidence for the low-noise capability of parametric amplifiers, but theoretically there could be extremely low noise.
So I decided I could demonstrate it. I had enough background experience for the multi-frequency circuitry — microcircuitry, also negative resistance, then negative resistance amplification — that I could handle this very tricky device. Then we decided. I quickly designed the circuitry, and our semiconductor microwave group developed reasonably good microwave diodes for the military application. I received a good diode and did the experiment. Less than three weeks after I joined Bell Laboratories I demonstrated low-noise capability. Eventually this news spread all over the Bell Laboratory. Important men visited my laboratory. That is how my work started. I didn't intend to switch when I joined Bell Laboratory. I would have worked on the microwave tube equipment for a few years at least, but right after I joined Bell Laboratory I switched to semiconductors, in the electron tube laboratory.
Aspray:
Why don't we stop here and continue this at some point in the future.
Uenohara:
Thank you.
