Low-Cost Multiparameter Optical Performance Monitoring Based on Polarization Modulation

A novel technique to conduct optical performance monitoring of WDM networks is proposed, implemented, and evaluated. The method is based on channel-individual polarization modulation of the wavelength channels at the transmitter, which enables low-cost monitor nodes consisting only of one polarizer followed by low-speed electronics. Despite the few optical components, the channel Stokes vectors can be measured and subsequently channel power, wavelength, optical signal-to-noise ratio, differential group delay are obtained. The Stokes vector precision is measured to be 2 degrees (rms), channel power accuracy +/-0.1 dB with a 20-dB dynamic range, and the wavelength accuracy is 30 pm. The OPM system was implemented in the field to monitor five WDM channels in an 820-km-long installed transmission link.