High Resolution PNC-OFDR With Suppressed Fading Noise for Dispersive Media Measurement

We show that fading noise in phase-noise compensated optical frequency domain reflectometry (PNC-OFDR) can be effectively reduced by applying an optical comb light source without any degradation in the reflectometry performance. The optical comb light source provides broad wavelength tunability, which is required for the frequency shift averaging (FSAV) for fading noise reduction while maintaining a narrow linewidth of the fiber laser used as a seed lightwave. We also clarify that PNC-OFDR with a reference interferometer simultaneously compensates for both phase noise and group velocity dispersion (GVD) induced by wideband measurement and a dispersive medium. These PNC-OFDR functions enable us to realize a high accuracy measurement of Rayleigh scattering level with low fading noise and high spatial resolution over 10 km range.