TY - JOUR T1 - Investigation of Amplification Parameters in Q-switched Fiber Oscillator-Amplifier Systems TT - JF - ijop JO - ijop VL - 14 IS - 2 UR - http://ijop.ir/article-1-427-en.html Y1 - 2020 SP - 155 EP - 162 KW - Gain coefficient KW - Saturation power KW - End-pumped KW - Side-pumped KW - distributed KW - Q-switched KW - Fiber laser KW - Master-oscillator power-amplifier. N2 - In this paper, an analytical model is presented to compare the monolithic end-pumped and distributed side-pumped arrangements in the master oscillator power amplifier (MOPA) of Q-switched (QSW) double-clad (DC) ytterbium (Yb)-doped fiber system. First, the time-dependent rate equations are solved numerically by the finite difference method and the output pulse characteristics are obtained. For more amplifying, the laser pulse is injected into the amplifier and the gain and saturation coefficients are obtained by using the best fitting between the outcoming data from solving rate equations and the transient amplification relation, based on the least squares method (LSM). Finally, the dependence of pump power and dopant concentration on the cavity amplifying parameters are investigated. M3 10.52547/ijop.14.2.155 ER -