Patent ID: 9112604
Filing Date: 2015-08-18
Classification: H04B

Abstract:
1. A method for determining an in-band noise parameter on an optical signal-under-test (SUT) propagating along an optical communication link and comprising a data-carrying signal contribution of any arbitrary degree of polarization and a noise contribution within an optical signal bandwidth, the method comprising: measuring a test optical spectrum trace of said optical signal-under-test at a test point along said optical communication link using an optical spectrum analyzer, said test optical spectrum trace corresponding to a spectral range encompassing at least a portion of said optical signal bandwidth; obtaining a reference optical spectrum trace of a reference signal comprising a data-carrying signal contribution spectrally representative of the data-carrying signal contribution of said signal-under-test, and a noise contribution which is at least approximately known over said optical signal bandwidth; estimating a spectral shape trace of said data-carrying signal contribution in said signal-under-test using said reference optical spectrum trace; using a processing unit, mathematically discriminating said data-carrying signal contribution from said noise contribution in said signal-under-test, within said optical signal bandwidth, using said spectral shape trace and said test optical spectrum trace; and determining said in-band noise parameter on said optical signal-under-test at least from the mathematically discriminated noise contribution.