| 摘要 |
PURPOSE:To reflect an optical signal on the occurrence of a line fault in a repeater employing an optical direct amplifier amplifying directly the optical signal without conversion of the optical signal into an electric signal CONSTITUTION:When a discontinuity fault takes place between stations A and B in an incoming line, since an optical signal is interrupted at the station B, an input interruption detection circuit 13 detects an input interruption and its control signal is used to open an optical shutter 14W, then an optical signal travels to an incoming photocoupler 2E. An optical signal for an outgoing line is reflected in the photocoupler 2E and sent to the incoming line. Furthermore, the input interruption signal is used to control a stimulation semiconductor laser 10W of the station B so as to prevent current flowing and the optical signal being an output of a photocoupler 2W is attenuated by a wavelength split multiplexer 6W and cannot reach the outgoing (W) of the station A. Similarly, an input interruption detection circuit 13W of the station A is operated and the optical signal inputted to an incoming line (E) of the station A is reflected and sent to an outgoing line of the station A. |
