Generation of sub-50 fs, 1.3 μJ, 110 GHz pulse burst in a gain-managed nonlinear Yb-doped fiber amplifier

We demonstrate a compact burst-mode fiber laser capable of generating ultrashort pulse trains with intra-burst repetition rates exceeding 100 GHz. Stable high-frequency burst operation is achieved through a 45° fusion splice between polarization-maintaining fibers. Based on gain-managed nonlinear amplification, the system delivers a 1.3 µJ burst energy consisting of eight 43 fs sub-pulses, with a 26 W average power at a 20 MHz burst repetition rate. To the best of our knowledge, this represents the highest intra-burst repetition rate achieved for sub-50 fs pulses from a fiber laser. The proposed laser exhibits great potential for high-throughput and high-precision micromachining.