Thulium doped fiber laser near 2 micron is of great interest because of the potential possibility of combining high efficiency, high output power, and retina safety together. This proposal is for the development of new Tm-doped glass fiber for efficient high power 2nmicron fiber laser capable of generating an output power of up to thousands watts. The doping concentration of the proposed glass fiber can be very high, which will result in the so-called cross relaxation energy transfer of thulium, dramatically improving the quantum efficiency. In Phase II, we will design and develop new Tm-doped glasses, measure the spectroscopic properties of thulium ions, characterize the cross relaxation energy transfer, demonstrate quantum efficiency of approximately 200%, and fabricate fiber perform and single mode fibers based upon Phase I results. We will realize efficient near 2 micron laser pumped with multi-mode 800nm laser diodes by optimizing fiber parameters, and demonstrate high power 2 micron fiber lasers. Successful development of such highly efficient high power 2 micron Tm-doped glass fiber laser with output power of kilowatts level would revolutionize the fiber laser development and enable many new applications.
Keywords: Thulium, Thulium Ions, 2 Micron Laser, 2 Micron Fiber Laser, Cross-Relaxation, Fiber Laser
