140 Khz, 1.2 Ps Pulses From An All-Pm Yb-Doped Fiber Master Oscillator-Power Amplifier

We report on an environmentally stable mode-locked all polarization maintaining fiber laser with a nonlinear amplifying loop mirror (NALM) at a ultralow repetition rate. Experimentally, using different cavity lengths we have achieved stable mode-locking at different repetition rates. By carefully adjusting the length of the total fiber of NALM, we achieve stable broadband pulse trains with a repetition rate as low as 140 kHz. The pulses can be further amplified up to 27 mu J and compressed down to 1.16 ps. The laser system has potential application for industrial application.