Method and apparatus for controlling optical signal power in response to faults in an optical fiber path

A method for controlling optical signal power supplied by a network element disposed along an optical fiber path, the method comprising the steps of:

• at an upstream position, sensing a downstream fault in the optical fiber path as a function of reflected optical signal power, wherein the reflected optical signal power corresponds to a downstream reflection of an optical signal supplied by the network element;
• and
• when the downstream fault has been sensed and, responsive only to the reflected optical signal power, automatically and variably reducing the optical signal power of the optical signal supplied by the network element at the upstream position by a predetermined amount by introducing a predetermined amount of loss into the optical fiber path to reduce the optical signal power below a predetermined level such that harm from an optical signal emanating at the downstream fault is substantially reduced.

An apparatus for controlling optical signal power supplied by a network element disposed along an optical fiber path, the apparatus comprising:

• a control circuit coupled to the optical fiber path at an upstream position, the control circuit being responsive to a reflected optical signal generated in the optical fiber path, wherein the reflected optical signal corresponds to a downstream reflection of an optical signal supplied by the network element,
• wherein, responsive only to the power level of the reflected optical signal exceeding a predetermined threshold indicative of fault occurrence, the control circuit automatically and variably reduces the optical signal power of the optical signal supplied by the network element at the upstream position by a predetermined amount, wherein the predetermined amount is based only on the power level of the reflected optical signal.

An apparatus for controlling optical signal power of an optical signal supplied by a network element disposed along an optical fiber path, the apparatus comprising:

• a control circuit coupled to the optical fiber path at an upstream position, the control circuit including an optical circulator for receiving a reflected optical signal generated in the optical fiber path, the control circuit being responsive to optical signal power of the reflected optical signal, the reflected optical signal corresponding to a downstream reflection of the optical signal supplied by the network element,
• wherein, responsive only to the optical signal power of the reflected optical signal exceeding a predetermined threshold indicative of fault occurrence, the control circuit automatically and variably reduces the optical signal power of the optical signal supplied by the network element at the upstream position by a predetermined amount, wherein the predetermined amount is based only on the power level of the reflected optical signal.

An apparatus for controlling optical signal power supplied by a network element disposed along an optical fiber path, the apparatus comprising:

• a control circuit coupled to the optical fiber path at an upstream position, the control circuit being responsive to a reflected optical signal generated in the optical fiber path, the reflected optical signal corresponding to a downstream reflection of an optical signal supplied by the network element,
• wherein, responsive only to the power level of the reflected optical signal exceeding a predetermined threshold indicative of fault occurrence, the control circuit automatically and variably reduces the optical signal power of the optical signal supplied by the network element at the upstream position by a predetermined amount by introducing a predetermined amount of loss into the optical fiber path to reduce the optical signal power below a predetermined level.