| 摘要 |
PURPOSE:To detect a failure of an optical fiber, by outputting monitor optical signals having different wavelengths at each optical repeater and detecting the presence of a monitor optical signal from each optical repeater or the strength of its receiving level at the receiving side. CONSTITUTION:An electric signal inputted to a terminal 1 is converted into an optical signal having a wavelength lambda0 at an optical transmitter 11 in an optical terminal device 10 and transmitted into an optical fiber transmission line 100. The optical main signal from the transmission line 100 is synthesized 22 optically with a monitor optical signal having a wavelength lambda1 from a monitor optical signal generator 23 at the optical repeater 20, waveform-shaped at the optical repeater 21 and transmitted to an optical fiber transmission line 200. The optical signal on the transmission line 200 is synthesized 32 with the monitor optical signal 33 having lambda2 of wavelength similarly at the optical repeater 30, waveform- shaped 31 and inputted to an optical terminal station device 40 via a transmission line 300. An optical branching filter 42 of the device 40 branches the monitor optical signals having wavelengths lambda1 and lambda2, which are inputted to a monitor optical signal receiver 43 to discriminate the presence of the monitor optical signal and the result is outputted from a terminal 3. |
