COHERENT OPTICAL RECEIVER Russian patent published in 1997 - IPC

FIELD: fibre-optical communication. SUBSTANCE: proposed coherent optical receiver has optical coupler composed of two optical directional couplers for formation of two channels, optical amplifier, phase-shifting element with control circuit, pumping source of optical amplifier, photodetector. It is inserted with optical delay line. Optical amplifier is built on two optical amplifiers as minimum, input and output ones, between which optical valve is installed. Second output of first optical directional coupler is connected to second input of second optical directional coupler which outputs are connected to inputs of photodetector. Phase shift between optical vibrations in channels is equal to odd number n/2. Pumping source is fitted with control circuit which output is connected to pumping source of optical amplifier and input is connected to output of photodetector. EFFECT: enhanced operational reliability. 1 cl, 1 dwg