Analysis of Tapered Laser Amplifiers with Linear and Nonlinear Angle-Opening Structures
(2.University of Chinese Academy of Sciences, Beijing, China 100049)
【Abstract】Using the split-step Fourier method to solve the steady-state traveling wave equation of a tapered semiconductor laser amplifier, we analyzed the optical and thermal characteristics of two kinds of laser amplifiers (with linear and nonlinear flare structures) by numerical simulation. By comparing the input current–output power curve, input power–output power curve, and the number of filaments of the two laser amplifiers, we studied the formation mechanism of filaments in the amplifiers, and the reason of the different optical field distributions in the two laser amplifiers was explained. Results show that the nonlinear flare structure can not only make the gain distribution more consistent with the optical field distribution but also reduce the coupling between the reflected light and incident light at the edge of the waveguide. Furthermore, the tapered laser amplifier with the nonlinear flare structure has the higher optical–optical conversion efficiency and more stable mode output.
【Keywords】 laser technique; tapered laser amplifier; split-step Fourier algorithm; optical and thermal characteristics; light field mode; filament;
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