| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical noise monitoring apparatus that measures noise power in a narrow wavelength region in channel signals of DWDM (Dense Wavelength Division Multiplexing) signals. SOLUTION: This apparatus 10 is a an optical noise monitoring apparatus that measures noise power in a narrow wavelength region in channel signals of DWDM (Dense Wavelength Division Multiplexing) signals and receives DWDM signals to cascade the signals along multipoint carrier channels and then the signals are come into a series of multipass filters F1-F4 in the multipoint carrier channels. Each multipass filter F1-F4 chooses a predetermined narrow wavelength region in the channel signals of DWDM signals. Noise power in the predetermined narrow region is detected and S/N ratio is monitored by comparing the noise power with power in the channel signals. Therefore, the apparatus 10 provides a plurality of multipass filters F1-F4 having each reflecting surface to guide optical signals in the predetermined wavelength region through a plurality of optical filter channels. |
