In-Service Optical Time Domain Reflectometry Utilizing Raman Pump Source

摘要

An arrangement for providing real-time, in-service OTDR measurements in an optical communication system utilizing distributed Raman amplification. One or more of the laser diodes used to provide the pump light necessary to create optical gain is modified to also generate short duration pulses that ride above or below the conventional pump light. These short duration pulses (which co-exist with the pump light within the optical fiber) are used in performing OTDR measurements, with a conventional processing system used to evaluate reflected pulses and create the actual OTDR measurements.

主权项

1. An arrangement for performing optical time reflectometry (OTDR) within a communication system utilizing distributed Raman amplification provided by a Raman pump source that supplies continuous power pump light to generate optical gain for a propagating signal, the arrangement comprising
a pulse generator coupled to the Raman pump source, the pulse generator injecting pulses of a predetermined polarity, duration, modulation depth and repetition interval upon the supplied pump light such that the pulses propagate with the continuous power pump light along a span of optical waveguide to be measured while generating optical gain, the injected pulses propagating along the optical waveguide and creating a plurality of reflected pulses as a function of conditions along the optical waveguide; and a monitoring module responsive to the plurality of reflected pulses, the monitoring module including a photodetector for converting the reflected optical signals into an electrical reflection signal and a signal processing component for determining OTDR measurements from the electrical reflection signal.