SIGNAL CONVERTER, LIGHT TRANSMITTER, AND OPTICAL FIBER TRANSMISSION DEVICE

摘要

PROBLEM TO BE SOLVED: To perform signal conversion with high CNR, in which an AFC circuit is not required and a phase noise is suppressed. SOLUTION: Output light from a semiconductor laser 32 is branched into two portions by a first branching filter 35. One of two branched beams is subjected to phase modulation by a multi-channel image signal by a light phase modulator 33. The other of the two branched beams is subjected to intensity modulation by a microwave signal, using a light intensity modulator 34. The two branched beams are coupled by a second light branching filter 36. The coupled light is received by a light receiver 37, converted into a microwave signal which is subjected to phase modulation by a multi-channel image signal, and is outputted.