Switchable dual‐wavelength erbium‐doped fiber‐ring lasers using a fiber Bragg grating in high‐birefringence fiber

A simple switchable dual‐wavelength Er‐doped fiber‐ring laser using a fiber Bragg grating (FBG) written in high‐birefringence (HiBi) fibers is proposed. Due to the two‐peak reflections with orthogonal polarizations of the FBG, the polarization hole‐burning effect in the cavity is greatly enhanced. Experimental results show that a stable dual‐wavelength laser with very close wavelength separation (0.39 nm) can be generated at room temperature. Furthermore, the FBG in the HiBi fiber offers flexibility for selection of the laser wavelength. By adjusting a polarization controller, the laser can be switched between the stable single‐ or dual‐wavelength lasing operations.