Analysis of pulse amplification of ytterbium-doped fiber amplifiers by means of finite elements

The main purpose of this paper is to present the simple and fast method for simulating the characteristics of pulse amplification in ytterbium-doped double-clad fiber amplifiers with finite elements model FEMLAB package.The upper-level population distribution in the fiber,the pump power and the amplified spontaneous emission with 915nm forward pumping were studied by using the same parameters with the finite elements model fast Fourier transform.The transient output power,stored energy and gain of Gaussian pulse and square pulse were simulated.These results are in good agreement with those obtained according to fast Fourier transform.Furthermore,these results are more exact.The results show this method is convenient and fast.This method will offer valuable reference in design and parameter optimization of ytterbium-doped fiber amplifiers.