Tm~(3+)-doped fiber master oscillator power amplifier with broad tunability in pulse duration using an acousto-optic external modulator

摘要

We demonstrate a pulse-duration tunable Tm~(3+)-doped pulsed all-fiber master oscillator power amplifier (MOPA) operating at a central wavelength of 1908 nm. By using acousto-optic(AO) external modulation, the amplified laser pulse shows a tuning range having pulse durations from 66.5 ns to 8.0 μs and a repetition rate of 100 kHz-2 MHz. The laser achieved a maximum average power of 28.1Wand a corresponding energy of 28.1 μJ at 1MHz with a 3 dB linewidth of 0.63 nm and a beam quality factor ofM_x~2 =1.25 andM_y~2 =1.32. The ASE suppression ratio is 50 dB and the corresponding total amplifier gain is 27.5 dB. To the best of our knowledge, it is the highest average output power and slope efficiency (～51.0%) achieved usingAOexternal modulation in aTm~(3+)-doped pulsed fiber amplifier.