(Reposted from: NJU Heart of An Ideal, Jiangsu, on August 29, 2022, at 21:04, with original title: Scholar Interview | Jiang Wei: Only Truth Deserves Eternal Pursuit)
Editor’s note
On the 120th founding celebration of Nanjing University (NJU), General Secretary Xi Jinping wrote back to NJU young overseas returnees, inspiring them to inherit and promote the honorable spirit of the elder scientists who studied abroad and went back home to serve their country, to help building up the nation with science and technology, and to strengthen their cultural confidence. After decades of years, many memories of the past may have been faded out, but never will the light of faith. By learning the stories of NJU young scholars who have returned home from their studies at abroad, we hope to appreciate their choices made in their life and to admire the glory of the scientist’s patriotism at this special moment.
In this interview, we have invited Jiang Wei, professor and doctoral supervisor from College of Engineering and Applied Sciences, NJU, as our special guest.
Profile
Jiang Wei is a professor and doctoral supervisor from College of Engineering and Applied Sciences, NJU. He is also the deputy director of both Institute of Optical Communication Engineering of Nanjing University, and Jiangsu Provincial Institute of Optical Communication Engineering and Network Engineering. He focuses on silicon-based photonics and photonic crystals, works on physics of photonic devices, microsystem integration, and has made achievements on electro-optic modulators, one of the core technologies in silicon-based photonics. He led the project that realized the first high-speed electro-optical modulator for photonic crystals on silicon chip and lowered the drive voltage for the first time to the range available on a general-purpose silicon-based electronic chip. This work has been widely reported by dozens of media like Nature Photonics, EE Times and Laser Focus World. He has done pioneering research on the mechanism and power consumption of high-speed silicon-based electro-optical device. He has proposed a new idea and physical principle of high-density waveguide integration, and realized high-density waveguide integration with half-wavelength spacing on silicon-based waveguides, which was noticed by Phys.org. He has recently realized an optical phased array with half-wavelength pitch based on waveguide superlattices and developed the related theory, which blazes a trial for applications such as high-performance LiDAR and wireless optical communication. He has conducted in-depth research on the analytical theory of surface coupling and transmission coefficients of photonic crystals, silicon-based thermo-optics and electro-optical device theory. He has published more than one hundred papers in Nature Communications, Physical Review Letters, Optica, Appl. Phys. Lett. Opt. Express, Phys. Rev. B and other academic journals and international conferences. He has received the IEEE Region 1 Outstanding Teaching Award, the DARPA Young Faculty Award, NJU Charismatic Advisor Award, and the Ben Streetman Prize of the University of Texas. He is also one of Jiangsu Specially-Appointed Professors.
Studying and doing research in a foreign land was a long way to go.
In 1992, Jiang Wei was enrolled in the Physics Program of the Department of Intensive Instruction, NJU. His choice to major in physics stemmed from his long-standing interests and talents. Growing up in a time when the spirit of scientists was revered and promoted, Jiang Wei harbored the dream of becoming a physicist ever since his high school years. “Physics can explain the world from a few relatively simple principles, which is very attractive to me.” Jiang Wei’s passion for physics led him to the Department of Intensive Instruction, NJU through early admission, and since then he has been devoted to physics research.
After two years of graduate education in China, Jiang Wei went to the United States for further study and research on physics in 1996. He received his master’s degree in physics from the University of Texas at Austin in 2000. Afterwards, he changed his research area and focused on electrical engineering, which was in greater demand and had broader prospects. He received his doctoral degree in electrical and computer engineering in 2005.
In response of the change of major, Prof. Jiang explains that physics researchers prefer to innovate at the fundamental level, which may take a long time but may, accordingly, lead to huge breakthroughs, while electronics people are more application-oriented, emphasizing the improvement of indicators and optimization of existing functions, both of which have their own merits. The Department of Electrical and Computer Engineering of the University of Texas has a research program in solid-state electronics that focuses on optoelectronic and microelectronic devices, which apply in, as commonly known, the chip industry. This program prefers to admit students with a background in physics. Under the guidance of Joe Campbell (whose teacher is one of John Bardeen’s students), Jiang Wei gradually built up his understanding of this frontier and of his own research through studying and practicing.
There was a big gap in terms of research funding and conditions between China and western countries in the 1990s. Prof. Jiang explains that scientific literature was hardly up-to-date and sufficient at home. By the time journals were available in China, it was several months later, making it difficult for people to access the latest first-hand information. “We did not have the access to the Internet for literature review back then. It was impossible to do research when you had to run to the physics book area on the top floor of the library, take out those thick journals and look them through one by one.” In order to have better research resources, Jiang Wei decided to study in the United States under the advice of his mentor. Prof. Jiang is glad to see that the gap of research conditions has been narrowing nowadays. Although the research funding and resources for Chinese teams may still be out-shadowed by top international research ones, it has been improved by leaps and bounds compared to more than 20 years ago.
New thinking, new methods, and new technologies
What Prof. Jiang has learned in those years overseas, he sums up with the word “new”.
In the Department of Physics and Department of Electrical and Computer Engineering at the University of Texas, Jiang Wei had the opportunity to attend the classes of Nobel Prize laureates and to discuss with scholars of the highest academic level and the most outstanding contributions. He was exposed with new scientific methods and ways of thinking, and the experience in an open and inclusive environment that encouraged creativity paved the way for his future scientific career.
One memorable detail in Prof. Jiang’s interview is that John B. Goodenough and Bryce DeWitt, both late elderly academicians, still insisted on teaching. Although they walked slowly on the podium and spoke slowly during the lecture, their logical deduction was lucid, and their theoretical capability strong. A complex problem would be made self-evident after their analysis. “The most important thing about listening to those professors is that you get to learn how they think, what kind of pace they move at, and how they choose to solve problems when encountering them.”
As he went further on the research path, Prof. Jiang said, he came into contact with scholars in many other areas and gradually realized what “first-class” actually means. It’s not about the research popularity, the impact factor or fame, nor the research output. Those scholars are truly “first-class” in their understanding of the issue they are working on.
Perhaps that’s one of the significance and impact of studying abroad - the opportunity to meet and interact with “first-class” scholars, who can help you hold up a mirror for reflection: What do you want to do? What problems do you want to solve? And how are you going to solve it?
▲ Professor Jiang Wei
After graduating with his PhD, Prof. Jiang had been considering to return to China. While he was excited about the rapid development in China, he was also aware that China still needed to catch up with its counterparts and needed to be built. Every generation has its own characteristic and spirit. Prof. Jiang has been harboring the ideal of serving the country since childhood, and that has inspired him to lead the world with Chinese technology. After the launch of the “Overseas High-Level Talent Recruitment Programs”, Prof. Jiang seized the opportunity and returned to his home country, continuing his research and teaching work at his alma mater, Nanjing University.
Words to the younger generations
Scientific research is a village to be explored.
Prof. Jiang is now working on silicon-based photonics and photonic crystals and developing popular devices like modulators for applications in optical communications, LiDAR, artificial intelligence, etc. Focusing on photonic crystals and waveguide superlattices, and reducing the device by one order of magnitude will have a huge impact on the performance improvement of optical chips, providing a solution to the fatal problem faced by the Chinese chip industry.
When it comes to his research career, Prof. Jiang said emotionally, “It was a long story.” He started to contact his mentor in his sophomore year and developed his research literacy, but it took a long way for him to really get started due to the limitations of research conditions in the old days.
In his junior year, while coping with the study pressure, he joined the experiment team and “went to the lab to see what was going on.” He thought it was “worth proving” a theoretical issue that no one cared to study on, and he did prove it. Although the related paper was rejected due to his lack of experience, he published it as his graduation thesis. The incident brought him a lot of confidence: “No one had proven this complex issue and yet I did, which shows that I am capable of making something”. His research experience in the team made Prof. Jiang ponder over the relation between theory and experiment, and made up his mind: “I would study those theories that can guide experiments, or those that have practical value.” This was how he started the scientific research.
When asked about whether ideas in scientific research depend on a flash of light, Prof. Jiang used an interesting analogy to explain the process of scientific research: “Let’s say now you are in a strange village, and you would only know one or two roads if you have no map or a rough one. You don’t know any path or track and it will take you a while to find your destination. However, if you’ve been wandering around the village for a week, it’s going to be very fast for you to find it.” There is no shortcut in scientific research. One could only have good ideas after spending a lot of time on it. People need to explore the strange village first, and gradually connect all the streets, paths and tracks. Only then can they have the so-called “experience” or “shortcut” when heading to the destination.
Prof. Jiang recalled an impressive moment in the summer of 2003 when they were working on an interface issue in photonic crystals. He paced up and down outside his apartment building for several consecutive evenings amid the American summer heat, until one day he finally found a solution. This might be called a "lightbulb moment", but it would never occur had he not been walking around the “village” for more than five years and figuring out all the tracks and paths. After the follow-up programming was completed and the problem successfully solved, Prof. Jiang was thrilled: “At that time, I felt that I finally got a foothold in the research community. Up until now, I think it is my biggest achievement in the theoretical study.”
▲ Professor Jiang Wei in the Lab
“I’ve always agreed with what my mentor said, which is, ‘if you are interested in something and you are paid to do it, you are the happiest person.’” For undergraduate students who are interested in pursuing a research career, Prof. Jiang believes that the most important thing is to find the field they are interested in, because only interest can help people lead the most ideal life on the road of doing research.
It also takes a positive mindset and the courage to face setbacks head on, otherwise people may find that everything becomes frustrating because most ideas end up in failure, he said. Find interests, and then work on them. It is bound to encounter difficulties, but so is a change of track. That is what the theory of probability tells us. “What else in the world is worth pursuing but the truth? Stick to passion and the truth. Even if you lose for the truth, at least you get to sleep sound, don’t you?”
▲ Professor. Jiang Wei and Partial Members of NJU Heart of An Ideal
Advice from senior scientists
“Find out where your interests and abilities lie, aim for a specific field to work on, and don’t get frustrated when difficulties arise. Remember this: What is easy must have been done already, so don’t get over yourself if you do it. As a student from NJU, you are supposed to do something special, which certainly leads to obstacles, but that’s where you can show your true value.”
Updated: August 31, 2022
