High-Power Photodiodes for Analog Applications

Abstract

High-power, high-speed photodiodes are being used in an increasing number of applications including fiber optic antenna links, radio frequency (RF) over fiber, and photonic generation of low phase noise microwave signals. The fact that the photodiode (PD) can be operated at high photocurrent levels provides several improvements in these systems including high dynamic range, high link gain, and low noise figure. In photonic wireless systems an antenna integrated photodiode can help to increase radiated RF power without the need for electronic amplification and hence simplify the RF circuitry at the antenna unit. To achieve high RF output power, various photodiode structures have been developed [1]–[4] among which the uni-traveling carrier (UTC) photodiode [3] has demonstrated high saturation current and high bandwidth. We have developed charge-compensated modified uni-traveling carrier (MUTC) photodiodes flip-chip bonded on high-thermal conductivity substrates to address the two primary effects that limit the RF output power of photodiodes, space-charge and thermal.