2-μm switchable, tunable and power-controllable dual-wavelength fiber laser based on parallel cavities using 3 x 3 coupler

We demonstrate a switchable, tunable and power-controllable dual-wavelength fiber laser in 2-mu m region based on parallel cavities using a 3 x 3 coupler. The laser topology is based on the parallel connection of fiber Bragg gratings (FBGs) using 3 x 3 coupler which act as two individual cavities, so that the dual wavelengths are tunable and switchable by adjusting the center wavelengths of FBGs and the cavity losses, respectively. With suitable cavity losses and input pumping power, we can obtain a 2-mu m switchable single- or dual-wavelength fiber laser. The proposed configuration has very good application prospects in the fields of atmospheric transmission, gas sensing, lidar and new wavelength-division-multiplexed fiber communication systems.