High-power high-bandwidth unitraveling-carrier photodiodes for high-frequency RF photonic links (Conference Presentation)

High frequency analog RF photonic links are desirable to reduce the size, weight and power of RF systems by offering the replacement of lossy, bulky coaxial RF cabling for lightweight, low loss and broadband optical fiber, particularly in applications such as avionics and naval RADAR systems, electronic warfare and distribution of low-jitter clocks or local oscillator signals. Freedom Photonics and the University of Virginia have developed high power, wide-bandwidth optical photodetectors operating in the 1550-nm wavelength range. These photodetectors are based on vertically illuminated modified uni-traveling carrier (MUTC) photodiode technology. The devices have been developed into fully packaged, fiber-pigtailed modules with optimization for high powers or high speeds. This paper will present the architecture and experimental results of our range of photodiodes. One family of devices focuses on high power applications. These include high-power photodiodes with 3-dB bandwidths of 25 GHz coupled with output powers in excess of 23 dBm, as well as 35 GHz photodiodes with output powers greater than 19 dBm. Another family of devices focuses on high speed applications, including photodiodes with 3-dB bandwidths of >65 GHz and >100 GHz. These photodiodes, used in a photonic link, have a major impact on peak performance. The high power-handling capability and high speeds of these devices support high link gain and large bandwidths, while the high linearity of these devices minimizes noise and signal distortion, maximizing spurious-free dynamic range (SFDR).