Non-polarization-maintaining fiber based single-polarization, single-frequency erbium-doped distributed-feedback laser

Phase-shifted fiber Bragg grating with high laser-induced birefringence is inscribed in a non-polarization-maintaining Er-doped silica fiber, by a novel femtosecond laser line-by-line direct-writing method. Efficient single-polarization, single-frequency distributed-feedback fiber laser is achieved.