A linear equalizer for high-speed APD-Based integrate-and-dump receivers

A linear minimum mean-square error (LMMSE) equalizer for avalanche-photodiode (APD) based integrate-and-dump receivers is designed to compensate for intersymbol-interference (ISI) introduced by the APD´s random impulse response. Recent work on the characterization of the joint probability distribution of the APD´s gain and buildup-time are adopted and utilized to determine the mean and correlation matrix of the APD-based receiver´s random impulse response. This LMMSE equalizer is shown to improve the bit-error-rate dramatically at high transmission rates, resulting in an improvement in the receiver sensitivity by approximately 2.3 dB at 15 GHz.