OPTICAL SIGNAL QUALITY SUPERVISORY SYSTEM

摘要

PROBLEM TO BE SOLVED: To obtain an optical signal quality supervisory system that can falsely supervise transmission line quality of a main signal simply and efficiently supervise the quality of the transmission line. SOLUTION: The optical signal quality supervisory system is provided with coupler that selects a bit rate of a supervisory control optical signal to be power then a bit rate of a main signal light so as to branch the supervisory control optical signal into two and with a transmission line system that uses this coupler to supervise the main signal falsely thereby supervising SD, EXC, APS, DCC with a simple circuit configuration.