Abstract: With current WDM technology a plurality of individual data channels exist on each fiber. Each of these data channels must be individually monitored in these WDM systems to ensure data signal quality. Monitoring of these signals is accomplished with the use of an optical performance monitor (OPM). An accurate known reference source is required for the OPM to provide reliable monitoring of signal data. The invention couples a reference signal simultaneously with a data signal and provides this combined optical signal to an OPM monitor for the purpose of obtaining high accuracy wavelength data at low cost.

Abstract: A spectrum, time and protocol optical power monitor is disclosed. This device utilizes a same photodetector to perform spectral optical monitoring of an incoming optical signal, as well as performing timing and protocol monitoring for preselected wavelength channels. Advantageously the device uses a same passband tunable optical filter for both the spectrum and timing/protocol measurements. The spectral response of the filter passband is deconvolved from the spectral scan in order to achieve improved spectral scan resolution, and the timing and protocol measurements are not degraded by the passband of the filter.

Abstract: Apparatus and method for monitoring an optical signal using a locally generated clock signal instead of a clock signal recovered from the optical signal. Numerous eye diagrams are generated based on a ratio between the known local clock and numerous estimates of the bit rate of the optical signal. The best eye diagram is selected, and the actual bit rate of the optical signal is then determined. Given the actual bit rate, time-varying performance of the optical signal may be monitored.