| 摘要 |
PURPOSE:To attain the monitor of an optical transmission line at in-service by adding an optical monitor signal generating circuit generating an optical monitor signal with a different luminous wavelength from a repeater to an optical recovery repeater, applying wavelength multiplex to the optical monitor signal via a monitor signal return optical fiber cable and looping back the signal to a terminal station. CONSTITUTION:A main signal inputted to an optical recovery repeater 1 of a monitor circuit additional recovery device 4 is sent to a signal system optical fiber cable 6 through reproduction relay processing and branched and fed to an optical monitor signal generating circuit 2. The circuit 2 utilizes the inputted main signal, generates a drive signal for a laser diode generating an optical monitor signal whose wavelength is lambda1 and the monitor signal whose wavelength is lambda1 is sent to a monitor system optical fiber cable 7 via an optical coupler 3. Similarly, an optical monitor signal whose wavelength is lambda2 is sent to the monitor system optical fiber cable 7 via the optical coupler 9 and two optical monitor signals with different wavelengths are thus subject to wavelength multiplex and fed to a terminal station. Then the optical transmission line is monitored without disturbing the transmission of the main signal. |
