Optical receiver

摘要

An optical receiver in which a failure in a certain channel affects no other channels is provided. An optical receiver inputs DQPSK optical signals supplied from the outside into each of first and second delay interferometers and reproduces optical output from the first and second delay interferometers as binary non-return-to-zero (NRZ) signals of first and second channels by first and second An optical receiving elements. The delay time of the first and second delay interferometers is performed a feedback control by a control system independent for each of the first and second channels.