Patent ID: 8639114

Claim:
An optical communication device for use in an optical communication system which uses a DPSK modulation-demodulation method, comprising: a number N (N: positive integer) of coding units for executing DPSK modulation coding with respect to the number N of input electric signals in N parallel, a multiplexing unit for multiplexing a parallel signal coded by said coding unit bit by bit on a time division basis to generate a serial signal, an electric-phase modulation optical signal conversion unit for converting a serial signal generated by said multiplexing unit into a phase modulation optical signal, a decoding unit for executing DPSK decoding of said phase modulation optical signal by comparison with an N-bit preceding optical signal, an optical-electric signal conversion unit for converting an intensity modulation optical signal decoded by said decoding unit into an electric signal, and a division unit for dividing an electric signal converted by said optical-electric signal conversion unit into the number N of signals bit by bit on a time division basis.