HYBRID SCM OPTICAL TRANSMITTER

PURPOSE: To utilize effectively a transmission band and to reduce clipping deterioration by an analog modulation signal. CONSTITUTION: The optical transmitter is provided with a signal limit section 9 applying a limit to an analog modulation signal and the analog modulation signal and a digital modulation signal being an output of the section 9 are subject to frequency multiplex processing, or with a signal limit section 9 applying a limit to a hybrid signal AM-QAM, or with a delay circuit 10 delaying the hybrid signal by a prescribed time delay and a clipping compensation section 11 detecting predicted clip intensity of the hybrid signal for a delayed period thereby generating a clipping compensation signal to block the clipping state of the laser beam output. Preferably, a clipping monitor control section 8 is provided, which detects the clipping state of a laser beam based on a monitor signal MS of the laser beam output and generates a control signal CS used to block the clipping state based on the detection, controls the limit of the signal limit section 9 or the compensation quantity of the clipping compensation section 11.