OPTICAL TRANSMISSION METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical transmission method that can set a valid optical modulation degree to an actual optical transmission system while taking an amplitude modulation characteristic of an AM video signal into account. SOLUTION: A frequency multiplexer section 13 frequency-multiplexing an AM video signal generated by AM video signal sources 111-11p and a 64 quadrature amplitude modulation QAM signal generated by 64QAM signal sources 121-12q, an electrooptic conversion section 14 converts the frequency-multiplexed signal into an optical intensity modulation signal, which is emitted to an optical transmission line 15. This optical intensity modulation signal is satisfied with a 1st condition where an optical modulation degree at which the AM video signal receives a required CNR or over is assigned to a carrier of the analog AM video signal, a 2nd condition where an optical modulation degree at which distortion of the AM video signal in its transmission band is a required value or below is assigned to a carrier of the AM video signal and the 64QAM signal, and a 3rd condition where an optical modulation degree at which each 64QAM signal attains required quality is assigned to the carrier of the 64QAM signal.