In-band impairment measurement via Varied-SOP polarization-resolved Optical Spectrum Analysis

We review a novel measurement concept, based on the acquisition of multiple polarization-analyzed optical spectra corresponding to different polarization-analyzer orientations, or equivalently to varied states of polarization (SOPs) of the light impinging upon the analyzer. This approach denoted “Varied-SOP polarization-resolved Optical Spectrum Analysis” (VSOP-OSA), enables several types of in-band optical impairments to be quantified. In particular, it permits accurate and rapid measurement of optical signal to noise ratio (OSNR), differential group delay (DGD), and inter-channel-induced nonlinear effects (NLE) in term of NLE-induced signal depolarization.