Memorial Tributes: Volume 27
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  • John Dallesasse
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  • ROBERT D. BURNHAM (1944-2023)
    ROBERT D. BURNHAMROBERT D. BURNHAM

     

    BY JOHN DALLESASSE
    SUBMITTED BY THE NAE HOME SECRETARY

    ROBERT DANNER BURNHAM, a leading pioneer in the metal-organic chemical vapor deposition (MOCVD) growth of epitaxial structures for high-power semiconductor lasers, passed away on June 29, 2023, in Fort Collins, Colorado. His pathbreaking contributions led to the successful commercialization of high-power, high-efficiency semiconductor lasers using quantum well heterostructures in the aluminium gallium arsenide-gallium arsenide (A1GaAs-GaAs) material system. These breakthroughs ultimately enabled watt-level semiconductor diode lasers used in broad-ranging applications that include optical pumping of fiber lasers used in marking, welding, and drilling.

    Robert was born on March 21, 1944, in Havre de Grace, Maryland, with his twin brother at a military base during World War II, and he and his siblings were raised in Edwardsville, Illinois. From there Robert went to Urbana, Illinois, where he studied electrical engineering at the University of Illinois at Urbana-Champaign. His talent and insight were recognized by Nick Holonyak Jr. (NAE 1984), who became his Ph.D. advisor. Working with Professor Holonyak, Burnham was the first to demonstrate that compound semiconductor quaternary materials (semiconductors formed using four elements) in the Ga1 xAlxAs1-yPy material system could be used to form high-performance double-heterostructure semiconductor lasers, and he was also the first to demonstrate the growth of laser-quality indium gallium phosphide (InGaP). The demonstration of laser-quality quaternary materials opened the door to research on related materials, ultimately leading other groups to work on materials and devices spanning today’s telecommunications wavelength bands.

    From Illinois Robert went to the Xerox Corporation’s Palo Alto Research Center (Xerox PARC), where he became one of the early pioneers in the MOCVD growth of semiconductor laser diodes. At Xerox PARC with William Striefer and Don Scifres (NAE 1997), Burnham worked on the development of distributed Bragg reflector semiconductor lasers and was the first to demonstrate electrically pumped, distributed-feedback lasers. The capability of distributed-feedback lasers to operate at a single wavelength has subsequently enabled the use of semiconductor lasers as the optical sources in wavelength-division-multiplexed long-haul and metropolitan-area fiber optic networks. The use of distributed-feedback lasers in optical communications networks has enabled both high data capacity and long link distance — critical factors for practical data transmission. This team further proposed that such lasers could be made in a vertically emitting geometry well before the application of semiconductor distributed Bragg reflectors to vertical-cavity surface-emitting lasers (VCSELs) and received the first patent on vertically emitting lasers (U.S. Patent 4,309,670). This patent, which had an application date preceding the first published work on VCSELs, disclosed many of the key structures present in modern VCSELs. VCSELs are now broadly deployed in enterprise networks, data centers, smart phone facial recognition, and optical “mice” and have potential use in autonomous vehicles. For this work Burnham was co-recipient of the Rank Prize for Opto-Electronics in 2002 with Dr. D.R. Scifres and Prof. K. Iga (NAE 2007).

    Burnham’s further work at Xerox PARC was instrumental in enabling the demonstration and commercial success of high-power, high-efficiency semiconductor lasers. Through his work on the MOCVD growth of AlGaAs-GaAs quantum well lasers, he was able to demonstrate wafer-scale production of laser-quality material with low laser threshold, high efficiency, and high uniformity. This led the team at Xerox PARC to demonstrate the first watt-class continuous wave semiconductor lasers at a time when all other diode lasers were only capable of emitting a few milliwatts of optical power. This breakthrough ultimately led to the founding of SDL Inc. in 1984. Today, this same MOCVD-grown quantum well diode laser technology is used to power rare-earth-doped fiber lasers, with uses ranging from low-power laser marking to multikilowatt lasers for welding, drilling, cutting metals, and more. This laser diode fabrication method is now the primary technology used to produce lasers for laser machining applications.

    Dr. Burnham has over 300 publications and 80 patents. In recognition of the impact of his work, Robert has been awarded numerous honors, including election to the National Academy of Engineering, co-recipient of the IEEE Jack A. Morton Award (1985) “for contributions to electrically pumped distributed feedback lasers and high-power phase-locked laser arrays,” election as a fellow of the IEEE, the Xerox President’s Award (1986) for “research leadership which has given Xerox a leading edge in the commercial fabrication of high-power solid-state lasers,” election as a fellow of the Optical Society of America (now Optica), and receipt of the University of Illinois at Urbana-Champaign Electrical and Computer Engineering Distinguished Alumni Award (1992). Over the course of his career Dr. Burnham led technical teams at Xerox Corporation Palo Alto Research Center and Amoco Technology Company and was co-founder of a technology company working on the commercialization of III-V oxidation for electronic-photonic integration and laser fabrication.

    Robert and Loretta Ann (Lori) were married July 25, 1997, and retired from Wheaton, Illinois, to Estes Park, Colorado, in 2000. Robert found joy in designing and overseeing the construction of their home. Once the home was completed he began designing extensive and elaborate gardens in the surrounding yard, and he worked for years to bring his dream to fruition in the challenging high-altitude climate and diverse wildlife of Estes Park. An avid member of the local gardening community, he became best known as having the garden with approximately 180 varieties of colorful peonies blooming all around the house in late June to early July. No visit by friends and family to the Burnham home was complete without a tour of the garden, and as any visitor to his gardens would readily attest, it looked like “fairyland.” He enjoyed being a member of the Estes Park Garden Club, served as treasurer for a spell, and loved sharing information and participating in garden tour events and local public library presentations. “Dr. Bob,” as he was affectionately known to his friends, was also known for his appreciation and knowledge of fine wine, knowledge that stemmed, in part, from his experience as a commercial wine maker as a co-founder in the mid-70s of Sommelier Winery in Mountain View, California. As a testament to his winemaking abilities, the wines Robert made are still being enjoyed by his friends and family some 40 years later. Robert was an ace ping-pong player and a member of the Ping Pong Club in Estes Park; he and Lori loved to dance and were members of the Friday Niters Dance Club for 12 years. His friends will remember him for his warm, easygoing, quiet nature, his profound intelligence and creativity, and his uncomplaining acceptance of adversity.

    Robert is survived by his wife, Lori Burnham; his son, Benjamin Burnham (Margaret) of Mt. Prospect, Illinois; his daughters, Kimberly Burnham of Minneapolis, Minnesota, and Jennifer Goldfarb (Ariel) of Evanston, Illinois; his twin brother, George Burnham (Kathryn) of Fort Collins, Colorado; his brother, Douglas Burnham (Catherine) of Stoke-on-Trent, United Kingdom; his former wife, Kyungsoon Kim Burnham of Wheaton, Illinois; and five grandchildren. He is also survived by many nieces, nephews, and cousins. Robert was predeceased by his parents, Hugh and Margaret Burnham; his two sisters, Mary Jane Neibel and Joyce Malisch; and his stepmother, Donna Burnham.