Modeling laser-diode-pumped Tm^(3+)-doped fiber amplifiers

A theoretical model is developed for the laser-diode-pumped Tm^3+-doped fiber amplifier,and a set of ordinary differential equations (ODEs) governing the dynamics of dual-wavelength pumping scheme (1.4 μm+1.56 μm) based on the rate equations and propagation equations was established.The relationship between the spectra gain and pump power was described and analyzed by numerically solving the ODEs.Spectral gain as a function of longitudinal position along the fiber was given to optimize the fiber length; spectral gain per unit length,and fractional inversion were used to explain the gain shift property of TDFA.The theoretical results agree well with the experimental data.