A new AOM used for all-fiber high power pulsed fiber laser

Abstract

A new fiber coupled AOM for high power Q-switched fiber laser is proposed and experimentally presented. Each end of the AOM has a fiber collimator. For its particular structure, amplified spontaneous emission (ASE) and other deleterious nonlinear processes such as stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in high power pulsed fiber laser can be easily suppressed. Based on our proposed acoustic-optic modulator (AOM), the 3dB line width of the fiber laser can be narrowed to only 0.1nm, which made it suitable to be used as the seed in master-oscillator power amplifier (MOPA) configuration based all-fiber pulsed fiber laser. When the repetition rate is 20 kHz, 2W output from the fiber laser can be achieved. Full width at half maximum (FWHM) of the fiber laser's pulse is 56ns and the peak power of the fiber laser is nearly 1.8kW. When the fiber laser is used as the seed of a high power fiber laser, 20W with 20 kHz repetition rate pulsed fiber laser has been obtained. The pulse width is nearly 100ns and the peak power can reach as high as 10kW. Based on the proposed technique, mature product of the pulsed fiber laser with this configuration has been successfully implemented.