Title :
Experiment and Numerical Modeling of High-Power Passively Q-Switched Ytterbium-Doped Double-Clad Fiber Lasers
Author :
Pan, Lei ; Utkin, Ilya ; Fedosejevs, Robert
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Alberta, Edmonton, AB, Canada
Abstract :
Two high-power and high-repetition-rate passively Q-switched Yb-doped double-clad fiber lasers have been demonstrated with small (5.4 ¿m) and medium (10 ¿m) core diameters using Cr4+ :YAG as an external saturable absorber. At a pump power of 13.8 W, 7.8 W single-mode outputs have been obtained with a pulse repetition rate of 120 kHz, pulse energy of 65 ¿J , and pulse duration of 116 ns. A theoretical model is developed to predict the laser spectrum and numerically simulate the output characteristics versus pump power. The focused beam in Cr4+:YAG is assumed to have a Gaussian profile and is analyzed using traveling wave rate equations. The effect of amplified spontaneous emission is also investigated in the simulation, which shows reasonable agreement with experimental observations.
Keywords :
Q-switching; chromium; fibre lasers; optical focusing; optical pumping; optical saturable absorption; superradiance; yttrium compounds; Gaussian profile; YAG:Cr; amplified spontaneous emission; beam focusing; external saturable absorber; high-power fiber lasers; laser spectrum; numerical modeling; passive Q-switching; power 13.8 W; single-mode outputs; size 10 mum; size 5.4 mum; theoretical model; traveling wave rate equations; ytterbium-doped double-clad fiber lasers; Chromium; Fiber lasers; Laser excitation; Laser modes; Laser theory; Numerical models; Numerical simulation; Power lasers; Predictive models; Pump lasers; Cr $^{4+}$:YAG saturable absorber (SA); Q-switched lasers; modeling; ytterbium (Yb) fiber;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2009.2028031
