Professor Campbell’s technical area is photodetectors. At present he is actively involved in single-photon-counting APDs, Si-based optoelectronics, high-speed low-noise avalanche photodiodes, high-power high-linearity photodiodes, ultraviolet analanche photodiodes, and solar cells. He has coauthored ten book chapters, 400 articles for refereed technical journals, and more than 400 conference presentations. Professor Campbell teaches graduate and undergraduate courses on lasers and optoelectronic components. In 2002 Professor was inducted into the National Academy of Engineering.