Signal deformation measurement on polarization-multiplexed signals

摘要

There is provided a method and an apparatus for determining quality parameters on a polarization-multiplexed optical signal based on an analysis of the power spectral density of the Signal-Under-Test (SUT). The method is predicated upon knowledge of the spectral shape of the signal in the absence of significant noise or spectral deformation. This knowledge is provided by a reference optical spectrum trace. Based on this knowledge and under the assumption that ASE noise level is approximately constant in wavelength over a given spectral range, the spectral deformation of the signal contribution of the SUT may be estimated using a comparison of the spectral variations of the optical spectrum trace of the SUT with that of the reference optical spectrum trace.

主权项

1. A method for determining a quality parameter characterizing a polarization-multiplexed optical signal-under-test (SUT) propagating on an optical communication link and comprising at least a data-carrying signal contribution and an Amplified Spontaneous Emission (ASE) noise contribution within an optical signal bandwidth, the method comprising:
measuring, using an optical spectrum analyzer, a test optical spectrum trace of said optical signal-under-test corresponding to a test point along said optical communication link, said test optical spectrum trace extending over a spectral range encompassing at least a portion of said optical signal bandwidth; using a computing device: obtaining a reference optical spectrum trace corresponding to a reference signal; estimating a spectral deformation of said signal contribution of said signal-under-test compared to said reference optical spectrum trace, within said spectral range, using said reference optical spectrum trace and said test optical spectrum trace, wherein the spectral deformation is at least partially induced by non-linear effects; and determining said quality parameter at least from the estimated spectral deformation; and outputting the determined quality parameter.