Return loss measurements of WDM filters with tunable coherent optical frequency-domain reflectometry

Reflectivity measurements of wavelength-division multiplexed (WDM) filters were performed with polarization independent coherent optical frequency domain reflectometry (C-OFDR). The spectral resolution of 0.012 mn allowed to characterize side lobe spacing and reflectivity with 90-dB dynamic range. The off-channel reflectivity was also measured for estimating the interchannel crosstalk in WDM systems and the experimental results were fitted to a theoretical equation, extracting the physical parameters of the filter.