Birefringence effect of optical fiber laser with intracore fiber Bragg grating

Abstract
The spectra of Nd/sup 3+/- and Pr/sup 3+/-doped fibre lasers utilizing an intracore Bragg grating reflector written at 1.08- mu m Bragg wavelength and a dichroic mirror for cavity feedback have been investigated under 0.6-GHz resolution. Two oscillating frequencies corresponding to two orthogonal linear polarization states of laser emission were observed. The frequencies and orientations of the two linearly polarized emissions could be changed by varying the fiber birefringence with an inline polarization controller. A phenomenological model is proposed to explain the experimental results.