High average/peak power linearly polarized all-fiber picosecond MOPA seeded by mode-locked noise-like pulses

Abstract

The characteristics of mode-locked noise-like pulses generated from a passively mode-locked fiber oscillator are experimentally investigated. By carefully adjusting the two polarization controllers, stable mode-locked noise-like pulse emission with a high radio frequency signal/noise ratio of >55 dB is successfully achieved, ensuring the safety and possibility of high power amplification. To investigate the amplification characteristics of such pulses, one all-fiber master oscillator power amplifier (MOPA) is built to boost the power and energy of such pulses. Amplified noise-like pulses with average output power of 423 W, repetition rate of 18.71 MHz, pulse energy of 22.61 μ J, pulse duration of 72.1 ps and peak power of 314 kW are obtained. Near diffraction-limited beam is also demonstrated with M 2 factor measured at full power operation of ~1.2 in the X and Y directions. The polarization extinction ratio at output power of 183 W is measured to be ~13 dB. To the best of our knowledge, this is the first demonstration of high-power amplification of noise-like pulses and the highest peak power ever reported in all-fiber picosecond MOPAs. The temporal self-compression process of such pulses and high peak power when amplified make it an ideal pump source for generation of high-power supercontinuum. Other potential applications, such as material processing and optical coherent tomography, could also be foreseen.