Polarization in low coherence interferometry

The polarization mismatch of the sample and reference arms in optical fiber based low coherence interferometry has critical effect on its depth resolution when the light source is partially polarized: When the polarization states of the two arms are matched the measured point spread function (PSF) is almost identical to the theoretical prediction; When their polarization states are mismatched the PSF can be so distorted that the depth resolution is degraded to several times of the theoretical value. When the source light is polarized the depth resolution becomes independent of the polarization mismatch.