High-Power 2 Micron Fiber Lasers

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 2ƒÝm 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 I, we will design and develop new Tm3+-doped glasses, measure the spectroscopic properties of thulium ions, characterize the cross relaxation energy transfer, demonstrate quantum efficiency of approximately 200%, fabricate fiber perform and single mode fibers, and demonstrate efficient near 2 micron laser pumped with multi-mode 800nm laser diodes. Successful development of such highly efficient high power 2ƒÝm Tm3+-doped glass fiber laser with output power of kilowatts level would revolutionize the fiber laser development and enable many new applications.