| 摘要 |
PURPOSE:To present an optical relay transmission line monitoring method and its device, which can eliminate a monitoring oscillator and can reduce circuits in the method and the device to monitor the disconnection of a transmission line which directly amplifies optical signals and to repeat them. CONSTITUTION:At the optical relay transmission line equipped with a direct optical amplifying means 1 directly amplifying signal beams, a beam splitting means 2 is provided to split the output beams of the direct optical amplifying means 1, a photoelectric converting means 3 is provided to detect optical signals inputted from the transmission line and to generate electric signals, an optical path switching means 4 is provided to connect the splitted beams from the beam splitting means 2 to the input of the direct optical amplifying means 1 when this electric signal is extinguished and to generate self-oscillation at the direct optical amplifying means 1 when the input signal beams from the transmission line are extinguished and by detecting an optical modulating frequency at that time at the terminal station of the transmission line, the disconnection of the optical transmission line is monitored. |
