Design of high linearity InGaAs/InP avalanche photodiode with a hybrid absorption layer structure

Abstract

Based on InGaAs/InP materials, a high linearity avalanche diode with a hybrid absorber layer was designed. The hybrid absorption layer is composed of intrinsic and neutral absorption layers. We analyzed the effect of the thickness ratio of different absorber layers, the doping concentration of the charge layer and the neutral absorber layer on the linearity of APD. The analysis and simulation results show that the hybrid absorption layer APD designed in this paper uses the depletion absorption layer and the neutral absorption layer with a thickness ratio of 0.5. The charge layer and the neutral absorption layer with doping concentrations of 9 × 1016/cm3 and 6 × 1017/cm3, respectively, effectively increase the linearity of the device while maintaining high responsivity. Under this structure, the linearity of the device is greater than −5.3 dBm with a gain of 11 and the responsivity is about 0.84 A/W at a gain of unity, which is about 50% higher than the normal SAGCM APD of the same responsivity.