title: Resonator based measurement technique for quantification of minute birefringence.
abstract: We present a new method for quantification of minute birefringence in high-finesse resonators. The method is based on observing the homodyne polarization mode beat at the output of the resonator. We show that the mode beat is generated by a phase mismatch of a polarization mode in the cavity and that the magnitude of the birefringence is proportional to the beat frequency. We demonstrate the sensitivity of the technique by measuring polarization properties of a twisted 0.275 m long single-mode fiber cavity. Maximum beat length of the fiber was found to be 10.6 m, which is almost 40 times longer than the length of the studied fiber.
authors.forename: Tuomo
authors.initials: T
authors.lastname: von Lerber
authors.forename: Hanne
authors.initials: H
authors.lastname: Ludvigsen
authors.forename: Albert
authors.initials: A
authors.lastname: Romann