OPTICAL TRANSMISSION SYSTEM

摘要

PURPOSE:To surely prevent the degrading of quality in optical transmission due to a change in a secular characteristic of a light emitting element without need of strict adjustment for a circuit parameter. CONSTITUTION:An optical transmitter is constituted of a drive circuit 12, a monitor optical signal reception circuit 18, a band pass filter 16 and a distortion detection circuit 14. A laser diode LD is subjected to brightness modulation with a multi-channel video signal S1 subjected to frequency multiplex inputted to the drive circuit 12 and outputs a modulation optical signal. The monitor optical signal reception circuit 18 and the band pass filter 16 extract a distortion component S4 at a center frequency band in the modulated optical signal and the distortion detection circuit 14 detects the distortion in the distortion component S4. The drive circuit 12 is subjected to feedback control so as to minimize the detected distortion.