The Theoretical and Experimental Study on High Power Quasi Single Mode Tm-Doped All-Fiber Laser at 1908 Nm

Abstract

Abstract Thulium-doped all-fiber lasers at wavelength of 1908 nm have developed rapidly because of more applications. In this paper, a quasi single mode thulium-doped quasi single mode all-fiber laser is reported, which can generate laser powers of 30.8 W in oscillator and 83.5 W in amplifier at wavelength of 1908 nm. The slope efficiencies are 43.93% and 55.65%, respectively. Besides, the effect of active fiber length on the conversion efficiency are studied theoretically and experimentally. The results show that optimal fiber length could improve the cross-relaxation process and pump utilization. Based on the thermal conduction equations, experiments theoretically study the cooling temperature and the coefficient of convective heat transfer impacted on thermal management to obtain high laser power output.