Theoretical modeling and simulation of Tm-doped double-clad fiber amplifier

Based on the finite-difference method, a typical Tm-doped double-clad fiber amplifier modeling is comprehensively analyzed through the rate equations and propagation equations. The impacting factors such as amplified spontaneous emission (ASE), wavelength and power of the seed, fiber length, pumping power and fiber facet reflectivity are discussed. Simulation results show that there exist the most suitable fiber length and pump power while the amplifier has the maximum output power and the best signal to noise ratio. Moreover, the influence of ASE can be effectively inhibited by reducing the fiber facet reflectivity, especially the front fiber facet reflectivity, choosing the proper seed wavelength and increasing the seed power. The theoretical models and simulation results presented in this paper have a certain reference value for the design and development of high-power Tm-doped double-clad fiber amplifiers.