Optical transmission apparatus and fault detection method

An optical transmission apparatus comprising:

• a non-reciprocal device including first to second ports, an optical signal input from the first port being provided to the second port, an optical signal input from the second port being provided to the first port;
• a dispersion compensator that is coupled to the first port of the non-reciprocal device and that conducts given processing to an optical signal input from the first port of the non-reciprocal device to provide the optical signal subjected to the given processing to the second port of the non-reciprocal device;
• a first monitor configured to monitor an optical signal output from the first port;
• a second monitor configured to monitor an optical signal output from the second port;
• and
• a fault determination device configured to determine a connection failure at the first port, the second port, or both of the non-reciprocal device and/or determine a connection state of the dispersion compensator to the non-reciprocal device, based upon a value monitored by the first monitor for the optical signal output from the first port of the non-reciprocal device and a value monitored by the second monitor for the optical signal output from the second port of the non-reciprocal device.