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

Abstract

Automatic reduction of optical signal power supplied by an upstream network element by a prescribed amount is achieved by capturing and processing reflected optical energy that is generated within the optical fiber path as a result of a downstream fiber cut, open connector, or other potentially hazardous discontinuity. Generally, the power level of the reflected optical signal is detected and measured in the optical fiber path and the optical signal power supplied by the upstream network element is automatically reduced. The optical signal power may either be reduced by an amount corresponding to the measured reflected optical signal power or may be completely shut off until the faulty condition is resolved. In one illustrative embodiment, an apparatus for automatically reducing or shutting off the optical signal power supplied by an upstream network element includes a directional optical transfer device disposed along the optical fiber path and coupled to the output of a network element, an optical power monitor for measuring the reflected optical energy received via the directional optical coupler as a result of a downstream fiber discontinuity, and control circuitry coupled between the power monitor and the network element to control the optical signal power being supplied by the network element based on the monitored power level of the reflected optical signal. The control circuitry may be analog, digital, or may be implemented using a microprocessor operating under software or firmware program control.