Tunable dual-wavelength fiber laser based on an MMI filter in a cascaded Sagnac loop interferometer

摘要

A widely tunable dual-wavelength erbiumdoped fiber laser based on a cascaded Sagnac loop interferometer incorporating a multimode interference filter is proposed and experimentally demonstrated in this paper. The mode selection is implemented by using the cascaded Sagnac loop interferometer with two segments of polarization maintaining fibers, and the wavelength tuning was achieved by using the refractive index characteristic of multimode interference effects. The tunable dualwavelength fiber laser has a wavelength tuning of about 40 nm with a signaltonoise ratio of more than 50 dB.