Theoretical analysis of characteristics for 2 μm Tm3+:Ho3+ co-doped silica fiber laser pumped by a 1550 nm fiber laser

We established a theoretical model of 2 mu m Tm3+:Ho3+ co-doped silica fiber laser pumped by a 1550 nm fiber laser based on the rate-equation theory and performed the numerical simulation using Runge-Kutta algorithm and Newton-Raphson algorithm. The intracavity power distributions of both pump and laser of the Tm3+:Ho3+ co-doped silica fiber laser based on the Tm3+:Ho3+ co-doped silica fiber supplied by the National Optics Institute in Canada (NOIC) were obtained. The effects of the output reflectivity R-4(lambda(s)) at the output laser wavelength lambda(s) and the concentrations of Tm3+ and Ho3+ in the fiber on laser output performance were analyzed. In order to achieve a high laser output power, the optimal R4(lambda(s)) of 0.13 was verified and the optimal Tm:Ho ratio of 1:2.4 was proposed. Finally, better output performance for the fiber laser based on the optimized Tm3+:Ho3+ co-doped silica fiber was obtained than the laser using the fiber supplied by the NOIC. This theoretical model and numerical simulation results will guide the fabrication of 2 mu m Tm3+:Ho3+ co-doped all-fiber lasers pumped by 1600-nm-band (1500-1750 nm) Er3+:Yb3+ co-doped silica fiber lasers. (C) 2012 Elsevier Inc. All rights reserved.