20-W AVERAGE POWER, HIGH REPETITION RATE, NANOSECOND PULSE WITH DIFFRACTION LIMIT FROM AN ALL-FIBER MOPA SYSTEM

摘要

In this article, we report an all-fiber master oscillator power amplifier (MOPA) system, which can provide high repetition rate and nanosecond pulse with diffraction-limit. The system was constructed using a (2+1) × 1 multimode combiner. The Q-Switched, LD pumped Nd:YVO{sub}4 solid-state laser was used as master oscillator. The 976-nm fiber-coupled module is used as pump source. A 10-m long China-made Yb{sup}(3+)-doped D-shape double-clad large-mode-area fiber was used as amplifier fiber. The MOPA produced as much as 20-W average power with nanosecond pulse and near diffraction limited. The pulse duration is maintained at about 15 ns during 50-175 kHz. The system employs a simple and compact architecture and is therefore suitable for the use in practical applications such as scientific and military airborne LIDAR and imaging. Based on this system, the amplification performances of the all-fiber amplifier is investigated.