Method for transmission and receipt of coherent light signals

摘要

The invention relates to a method for transmission and receipt of coherent light signals. Each subscriber is provided with an optical heterodyne detection circuit. An oscillation light of an optical local oscillator (3) is divided to a local oscillation light (4) for the heterodyne detection and a transmitting light (20) for data communication. A channel for those lights is selected from vacant communication channels. The transmitting light (20) may be obtained from a transmission light oscillator which is controlled by a control unit common to the optical local oscillator.