FAULT LOCATION ON OPTICAL AMPLIFIER SUBMARINE TRANSMISSION-SYSTEMS

This paper addresses some solutions to overcome the problems that aris e when optical time domain reflectometry (OTDR) is applied to optical amplifier submarine transmission systems. It designs a backscatter pat h that feeds the backscattering into the opposite line without causing any degradation in the main signal transmission. This paper proposes a new modulation format, FSK-ASK, and confirms that the proposed appro ach can both eliminate optical surge generation and improve OTDR perfo rmance. An FSK-ASK OTDR is applied to an 890-km commercial amplifier s ubmarine transmission system with a 90-km span. Field trials successfu lly demonstrate that the OTDR can locate a fault in all spans with a s patial resolution of 1 km after averaging the sum of 2(20) measurement s. The FSK-ASK OTDR proves to be very useful in maintaining a reliable submarine transmission system because it can locate subtle fiber anom alies along the entire length from a terminal end.