Polarization effects in optical microresonators

Polarization effects in different types of optical microresonators, namely, a microsphere, a microcylinder, a milled microresonator (MR), and a microbottle resonator, are studied in detail. A polarimetric setup was utilized to investigate the evolution of the transmission dips, polarization cross-coupling (PXC) peaks, and scattered light as the input polarization is varied. It is shown that the transmission dip and PXC minima are shifted with respect to the ideally expected input polarization angle. A theoretical model based on Jones matrix calculus was developed in order to identify the root cause of the observed effects. The modelling has attributed the observed shifts to the residual birefringence of the output part of the microtaper fiber used for evanescent coupling into the MRs. (C) 2019 Optical Society of America