Ciena Corporation
Balancing a pair of avalanche photodiodes in a coherent receiver

Abstract:

System and methods implemented in a coherent receiver having a pair of Avalanche Photodiodes (APD) include adjusting one or more of a reverse bias voltage (VAPD) on a P-path (VAPD.sub.P) and on an N-path (VAPD.sub.N) responsive to an output (P.sub.IN,CM) that indicates electrical power of an AC common-mode input signal; adjusting a Transimpedance Amplifier (TIA) common-mode AC response, Adj.sub.CM_AC_Response, responsive to an output (P.sub.OUT,CM) that indicates electrical power of an AC common-mode output signal; and/or adjusting one or more of VAPD.sub.P and VAPD.sub.N responsive to received signal Signal-to-Noise Ratio (SNR).