OPTICAL CODE COMMUNICATION SYSTEM

摘要

An optical code communication system comprises an optical transmitter, an optical receiver, and an optical transmission channel. The optical receiver has an optical mixing decoder for mixing a code light and a local oscillation light, branching the mixed light into an object light frequency and a nonobject light frequency, and outputting the lights and a detection addition/subtraction filter for detecting the object light frequency and the nonobject light frequency, filtering the intermediated frequency signals, subtracting one of the intermediate frequency from the other, and outputting the resultant frequency. The code light and the local oscillation light are coherent with each other between the optical frequency chips constituting the code light when detected. The light mixing decoder or detection addition/subtraction filter regulates the phase of the intermediate frequency signal within the pass band when filtered so that the output value or the absolute value of the intermediate frequency signal within the pass band when filtered is different when the optical receiver receives a code light modulated with a different value of the transmission data.