| 摘要 |
PURPOSE:To recover the fault of an optical subscriber system without using any optical switch by switching either optical transmission after modulating a sub carrier with a signal or direct optical transmission while using a variable optical transmitter and variable optical receiver. CONSTITUTION:Normally, variable optical transmitters 10 in subscribers 102-104 convert inputted burst signals to optical signals as they are and output them, and a variable optical receiver 11 in a station 101 is also operated in the state of receiving the normal burst signals. In this case, assuming that any fault is generated at the subscriber 104 and the wrong optical burst signal is sent out, for example, the variable optical transmitters 10 of the subscribers 102 and 103 are changed so as to send optical signals for which the sub carrier is modulated by the burst signal, and the variable optical receiver 11 in the station 101 also changes the operation so as to demodulate the optical signals for which the sub carrier is modulated. Thus, signals can be transmitted from the subscribers 102 and 103 to the station 101 by using the optical signal, for which the sub carrier is modulated, without being disturbed by the wrong optical burst signal outputted from the subscriber 104. |
