Some sixty people, including UC Santa Barbara faculty colleagues, alumni, and industry partners, convened at UCSB’s Loma Pelona Center on March 16 to honor emeritus professor Larry Coldren, a giant in electrical engineering and materials science, particularly as they relate to photonic integrated circuits and tunable lasers. Some 24 speakers took the podium over several hours to honor Coldren’s legendary contributions.
College of Engineering Dean Rod Alferness opened the event, titled “A History of PICs (Photonic Integrated Circuits) and VCSELs (Vertical Cavity Surface-Emitting Lasers),” before introducing Chancellor Henry Yang, who mentioned the following as just some of Coldren’s accomplishments.
He is a member of the National Academy of Engineering and the National Academy of Inventors, and a fellow of the Optical Society of America and the Institute for Electrical and Electronics Engineers. He was named to the latter before he even began the photonics work that would bring him worldwide renown. He spent thirteen years at Bell Labs, and came to UCSB in 1984, a move that one speaker described as “a risk he took that paid off; he saw UCSB as an up-and-coming university and wanted to help it grow.”
He spent two years as acting dean of the College of Engineering, was a co-founder of the Materials Department, and was named Fred Kavli Professor of Optoelectronics, making UCSB the first of now eighteen universities to host a Kavli Institute and named professor. He is part of the Institute for Energy Efficiency (IEE) at UCSB and has directed the Optoelectronics Technology Center, which he co-founded, since 1990.
Coldren has advised more than 70 PhD students, been issued more than 63 patents, and published more than a thousand papers, plus multiple book chapters and, in 1995, the seminal book Diode Lasers and Photonic Integrated Circuits, which has become a standard graduate-level text on the topic. His inventions have served as enabling technologies for some of the most widespread devices in the world, from iPhones to laser mice, to face recognition and fiber-optic networks. He cofounded two companies, Optical Concepts and Gore Photonics.
At the end of Chancellor Yang’s lengthy, but only partial, list of Coldren’s accomplishments, he said with a laugh, “I received one patent and it took ten years. I have no idea how Larry found the time to earn sixty-three and to do all the other things he did.”
Wguih Ishak, who played a key role in inventing the laser mouse at Hewlitt-Packard in 1995 and is currently Division Vice President & Director of Corning West Technology Center in Palo Alto, California, described Coldren as a man of “very few but very effective words” and the photonics center he has led at UCSB as “the very best in the world.”
Milan Mashanovitch, a former Coldren PhD student and current CEO of Freedom Photonics in Goleta, recalled his mentor's roots growing up on a large farm in Pennsylvania where he worked on all kinds of machinery and structures, “essentially mastering mechanical and structural engineering.” Coldren then attended Bucknell University, double majoring in physics and electrical engineering, the latter, said Mashanovitch, capturing Coldren’s characteristic love of a challenge and willingness to work far out of his comfort zone, “because it was a subject he knew little about.” Coldren earned a master’s and PhD in electrical engineering from Stanford while he was a fellow at Bell Labs.
Herb Kroemer, who earned a Nobel Prize for his seminal theoretical work on compound semiconductors, recalled that when Coldren came to UCSB when the university was “raiding Bell Labs,” in the wake of the 1982 breakup of the Bell conglomerate, he was hired to lead laser research, a key component of the serious semiconductor program Kroemer and colleagues envisioned. A big early challenge was how to emit usable light generated inside a laser diode. As Coldren’s work continued, Kroemer recalled, “It was clear how difficult it was to get the light out of the diode. I thought personally that it was very nearly impossible. Well, Larry did it.”
Kroemer’s longtime collaborator Art Gossard, an expert in growing semiconductor materials who came to UCSB and worked extensively with Coldren, described him as someone who, “knew where everything was going and was great at convincing other people how important the work was, bringing together great collaborators, and getting funding from federal agencies to see it through.”
John Bowers, another renowned UCSB professor and the Kavli Chair in Nanotechnology, who also leads the AIM Photonics West Coast Hub at UCSB and wrote more than a hundred papers with Coldren, joked, “As you probably noticed, I've been basically following Larry's footsteps for a long time,” before adding, “Thanks, Larry. It's been more than forty years. UCSB owes you so much not only for the research you’ve done, but also for bringing up the technology, from clean rooms to etching techniques to processing. It has benefitted all of us.”
Another student of Coldren’s, Greg Fish, who is now Distinguished Engineer at Juniper Networks Silcon Photonics in Goleta, recalled the first time he heard Coldren speak at a symposium when Fish was an undergraduate student at the University of Wisconsin, Madison. “After Larry explained how a tunable laser works, I remember thinking, This is one of the greatest ideas I’ve ever heard,” he said.
For all of Coldren’s remarkable conceptual, technical, and entrepreneurial brilliance, many of the 25 speakers who honored him also remarked on him as an extraordinary person.
“When I met Larry, I liked him right away, and who wouldn’t,” noted Jack Jewell of Bell Labs, “One of the things that really stands out is his smile. I think you were born with it, and all the doctors and nurses gathered around, saying, ‘Look at this guy.’”
Jonathan Klamkin, now an assistant professor in the Department of Electrical and Computer Engineering, spent a few years working in industry on the East Coast before coming to UCSB for his doctoral studies. He recalled that colleagues who knew he was interested in photonics and microcircuits said to him, “If that’s what you’re interested in, then you need to go work with Larry Coldren.” Klamkin started off as another one of Coldren’s students and has been here ever since.
“He was very good at setting you on a path and then getting out of the way,” said John Parker (PhD ‘12), who works as a silicon photonics engineer at Juniper Networks. “He rarely got into the nuts and bolts. Larry’s always been big on getting the message really clear, and then saying, ‘OK, figure this out. I’m going to do something else.”
Yoshi Nakano, professor at the University of Tokyo, seemed to be speaking for many in the room when he recalled the eight years he spent as an associate professor in the Electrical and Computer Engineering Department at UCSB as, “the most beautiful time in my life, thanks to Larry.”