| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical monitor device which does not need a new filter for monitor light extraction and is inexpensive. SOLUTION: Signal light of 1550 nm wavelength is transmitted in an optical transmission line 130 and signal light of 1554 nm wavelength is transmitted in an optical transmission line 131. These light is performed wavelength multiplexing by an optical demultiplexer/multiplexer 410 and is outputted to an optical transmission line 120, and also, it is partially branched by an optical branch 207. Wavelength multiplexed light that is branched is inputted to the next port of an optical port which is outputted to the line 120 among ports of the demultiplexer/multiplexer 410 through an optical transmission line 138. Monitor light of 1554 nm wavelength is outputted to the line 130 and monitor light of 1550 nm wavelength is outputted to the line 131 by a router function of the optical demultiplexer/multiplexer. Each monitor light is performed light branch by optical branch 205 and 206, and each wavelength light is inputted to an optical monitor 20 via optical transmission lines 136 and 137. Since the monitor light passes through the optical demultiplexer/multiplexer of a narrow transmission band, it is possible to supervise wavelength deviation and to measure a light level which does not include a natural emission light noise component. |
