OPTICAL FREQUENCY STABILIZING METHOD AND OPTICAL TRANSMITTER

摘要

PURPOSE:To make a modulated transmission optical frequency stable without being affected by a transmission signal by extracting a part of a spectrum of a modulated transmission light with an optical filter and detecting the frequency of the extracted light so as to apply negative feedback. CONSTITUTION:A transmission light extracted by an optical coupler 3 is given to an optical frequency filter 4, the optical frequency shift signal is detected by a photodetector 5 and fed back in negative to a laser control circuit 1. The laser control circuit 1 is constituted of amplifier 6, 7 whose band is identical to each other, a division element 8 and a laser driving circuit 9. The frequency of the modulated transmission light is made stable without being affected by a change in the transmission signal.