Patent ID: 7002735

Claim:
A method for detecting a connector disengagement of an optical fiber amplifier and a transmission optical fiber connected to the optical fiber amplifier, the optical fiber amplifier comprising a doped optical fiber and a pumping light source, and a transmission optical fiber comprising at least one connecting portion connected to an output of the optical fiber amplifier, the method comprising: measuring a reflection from the transmission optical fiber to the optical fiber amplifier, the reflection being given as a power ratio of a reflected light and an output optical signal; comparing the reflection to an allowable range between a first threshold that is greater than a predetermined reflection in the absence of a connector disengagement, and a second threshold that is smaller than the predetermined reflection in the absence of a connector disengagement; determining that there is no connector disengagement when the measured reflection is within the allowable range; and determining that there is a connector disengagement when the reflection is out of the allowable range.