One Degree of Freedom Fiber Ring Depolarizer

A single fiber ring depolarizer with one degree of freedom of adjustment is proposed by setting the bend-induced birefringence in the fiber ring as a half-wave plate and choosing proper coupling coefficient of the coupler. Depolarization can be realized by just rotating the whole set of the fiber ring. A 12-m fiber ring depolarizer is demonstrated to depolarize a Fabry-Pe¿rot laser with 10-m coherent length, and a degree of polarization of 1.5% is obtained.