High-power and highly efficient TM3+-doped silica fiber lasers pumped with diode lasers operating at 1150 nm

An output power of 1.74 W at 2.03 mu m was generated at a slope efficiency of 51% when a double-clad Tm3(+)-doped silica fiber laser was pumped with high-power 1150 nm diode lasers. Pump excited state absorption from the upper laser level populates higher energy levels allowing cross relaxation to repopulate the upper laser level at a quantum efficiency greater than unity and to limit losses relating to additional pump excited state absorption. The output power was scaled to 4.77 W when both ends of the fiber were pumped. (c) 2007 Optical Society of America.