Optical transmission system

An optical transmission system with a mechanism to locate a fault on an optical transmission line, comprising:

• (a) repeaters which relay optical signals over the optical transmission line, each repeater comprising:
• monitoring report signal generating means, responsive to a monitoring control command, for monitoring a current operating status and input/output signal conditions of said each repeater, and generating a monitoring report signal that contains results of the monitoring;
• and
• light pulse signal sending means, responsive to a troubleshooting control command, for sending a probing light pulse signal to the optical transmission line to locate a fault thereon, as well as a complementary light pulse signal that is complementary to the probing light pulse signal;
• and
• (b) an end station which controls optical signal transmission and remotely controls said repeaters, said end station comprising:
• (b1) a monitoring controller, comprising:
• monitoring control command sending means for sending the monitoring control command;
• and
• monitoring report processing means for monitoring the operating status of said repeaters by analyzing the monitoring report signals received therefrom, and identifying a faulty link section if any problem with the optical transmission line is detected;
• and
• (b2) a troubleshooting unit, comprising:
• troubleshooting command sending means for sending the troubleshooting control command to one of said repeaters that is located near to the identified faulty link section;
• Rayleigh backscatter measurement means for measuring a Rayleigh backscattered light caused by the probing light pulse signal, using the complementary light pulse signal as a reference for synchronization;
• and
• fault detection means for locating the fault on the faulty link section by analyzing the measured Rayleigh backscattered light.