Optical receiver, optical communication systems and coherent detection method

摘要

PROBLEM TO BE SOLVED: To provide an optical receiver, an optical communication system, and a coherent detection method capable of detecting one or plural rays of signal light coherent synchronously irrespective of fluctuations in phase or optical frequency, without transmitting local emitted light having a constant signal light to phase relationship along with signal light, nor using a dynamic optical phase synchronization loop of local emitted light.;SOLUTION: An optical receiver, an optical communication system, and a coherent detection method of the prevent invention are designed to work in such a way that plural rays of light equal in initial phase and phase noise term and differing in frequency by a prescribed amount are fed as pump light into a four wave mixing unit, from which plural rays of idler light derived by four wave mixing of signal light and pump light are output. Then, these output rays of idler light are optically detected, and an intermediate frequency signal generated by rays of the idler light together is sync detected with an electric signal which has had its phase synchronized with an electric signal which was used when generating the pump light.;COPYRIGHT: (C)2012,JPO&INPIT