FM LASER, PM BATCH CONVERTER AND DISTORTION MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a FM laser and a FM batch converter, having less distortion by a method where distortion is measured by symmetry of spectra of wide band FM signal waves. SOLUTION: When a signal sine wave signal is input so that a FM modulation index is close to about 5.1356 as a first zero, a shift amount between the FM modulation index in which an amplitude of a second side wave band of an light spectrum of output signal lights is zero and the FM modulation index in which the amplitude of - second side wave band is zero is set to be 0.015 or lower, whereby in a 40-channel image transmission, when a maximum multiplexed number N=11 and average modulation index mave=0.41, a composite secondary distortion of a FM laser applied to a FM batch converter CSO can be set to a specification value of -54 dB or less of an AM image transmission.