Thermally Induced Nonlinearities in High-Speed p-i-n Photodetectors

Abstract

Nonlinearities in the responsivity of high-speed p-i-n photodetectors at high photocurrents can limit the useful dynamic range in photonic systems. This letter describes a nonlinearity in the quantum efficiency in InGaAs photodetectors designed for applications at 1.5 μm is due to significant ohmic heating of the intrinsic region. Measured changes in responsivity of about 10% at photocurrents of 12 mA are attributed to a thermal bandgap shift, based on comparisons with temperature dependent measurements and a model of ohmic heating.