High-gain high-sensitivity resonant Ge/Si APD photodetectors

Abstract: In this paper we present a separate-absorption-charge-multiplication Ge/Si avalanche photodiode, which has a high gain-bandwidth product (e.g.,>860GHz at a wavelength of 1310nm). Such a high gain-bandwidth product is attributed to the peak enhancement of the frequency response at the high frequency range. From a small signal analysis, we establish an equivalent circuit model which includes a capacitance parallel connected with an inductance due to the avalanche process. When the APD operates at high bias voltages, the LC circuit provides a resonance in the avalanche, which introduces a peak enhancement