| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical output-interrupt detection circuit that can automatically accurately detect reduction in an optical output level so as to raise an alarm immediately. SOLUTION: In the optical output detection circuit that detects an output level of an optical signal according to a transmitting data signal, a flip-flop 5 that inputs a comparison signal Scomp resulting from comparing a voltage Spd obtained by converting an output level of the optical signal in an LD 1 with a reference voltage Vref at a terminal D and a signal Sdly obtained by delaying the data signal Sdata at a terminal C, and a signal Scell denoting a start time and an end time of a burst signal cell of the transmitting optical signal at a terminal R and outputs a signal Sdff, which is used to detect an output level of the optical signal. |
