Research on key technologies for 2μm band of thulium-doped fiber laser

Abstract Abstract The gain material of 2μm wavelength thulium-doped fiber laser is a thulium-doped fiber doped with rare earth element thulium. Rare earth doped optical fiber as gain medium is the basic structure of optical fiber laser. This type of laser is mainly composed of pump source, coupler, gain optical fiber doped with rare earth elements, cavity and other optical devices. The pump source is generally a combination of one or several high-power laser diodes. The light emitted by the pump source enters the gain optical fiber doped with rare earth elements through a certain pumping mode. The inversion of the number of particles occurs when the doped optical fibers absorb photons, and then the light waves stimulated from the doped optical fibers are emitted by the laser after the oscillation. Since the connection structure and parameters between optical fibers and optical components can be maintained stable over a long period of time, thulium-doped lasers do not need to be maintained regularly and are based on output power. They have smaller volume and weight, lighter weight and longer life than solid-state lasers. However, in general, the power of a 2μm wavelength thumbium-doped fiber laser is not too high, while a high-power 2μm wavelength thumbium-doped fiber laser can meet people’s needs and play a greater role. Therefore, improving the power of 2μm wavelength thumbium-doped fiber laser is an important direction for the development of thumbium-doped fiber laser. The energy level structure of thulium ion is analyzed, the doping concentration of thulium ion is studied, and the method to increase the power of a 2μm wavelength thulium-doped fiber laser is given.