Dual Polarization Interferometric In-Band OSNR Measurement

An in-band optical signal-to-noise ratio (OSNR) monitoring technique based on a Michelson fiber interferometer and a linear polarizer is presented in this letter. OSNR values of up to 25±0.5 dB were measured for 10-G nonreturn-to-zero-differential phase-OOK (NRZ-OOK) and NRZ-differential phase-shift keyed (NRZ-DPSK) signals without prior knowledge of the signal coherence properties. Measurements were also carried out with signals having 680 ps/nm of chromatic dispersion.