Performance monitoring in optical networks using Stokes parameters

A new technique for performance monitoring of optical wavelength-division multiplexing (WDM) networks is evaluated. By measuring the Stokes parameters as a function of wavelength, not only the conventional channel power spectrum is obtained, but also the state of polarization (SOP) and degree of polarization (DOP) of the channels. The information about the polarization provides additional monitoring capabilities, e.g., optical signal-to-noise ratio (OSNR) measurements within channels, polarization-mode dispersion (PMD) monitoring, error signal to PMD compensators, etc. The new method to measure OSNR is compared to the conventional measurement technique and is shown to be equivalent to, and in some particular cases even superior to the conventional measurement method.