Monitoring optical WDM-networks by using statistical methods

A novel method to monitor the performance of WDM channels in an optical network is presented. From the photo-diode current of a detected optical signal, an amplitude histogram is generated; the probability density function (PDF). By analysing the PDF, information is obtained about several performance parameters, including the optical power as well as the noise-levels on the bit-levels of the channels. A wavelength dependent attenuator has to be used to extract these performance parameters uniquely. Experimental evidence demonstrates that the method can be used to analyse at least three WDM channels simultaneously.