A SIMPLIFIED APPROACH TO TIME-DOMAIN MODELING OF AVALANCHE PHOTODIODES

A simplified algorithm for calculating time response of avalanche phot odiodes (APD's) is presented, The algorithm considers the time course of avalanche processes for the general case of position-dependent doub le-carrier multiplications including the dead space effect, The algori thm is based on a discrete time setting ideally suited for computer mo deling and can be applied to any APD structure. It gives a fast and ac curate estimation of the time and frequency response of APD's, As an e xample, the present method is applied to InP-InGaAs separate absorptio n, grading, charge, and multiplication (SAGCM) APD's, The variation of multiplication gain with bias voltage and 3-dB electrical bandwidth a t different multiplication gain obtained using the new algorithm show good agreement with experimental results, The algorithm can be used to study temperature dependence of APD characteristics and can he easily extended to calculate the excess noise factor.