In this work, we investigate an approach to scale up the output pulse energy in an all-polarization-maintaining 17.3 MHz Yb-doped fiber oscillator via implementation of a 25 µm core-diameter large-mode-area fiber. The artificial saturable absorber is based on a Kerr-type linear self-stabilized fiber interferometer, enabling non-linear polarization rotation in polarization-maintaining fibers. Highly stable mode-locked steady states in the soliton-like operation regime are demonstrated with 170 mW average output power and a total output pulse energy of ∼ 10 n J distributed between two output ports. An experimental parameter comparison with a reference oscillator constructed with 5.5 µm core-sized standard fiber components reveals an increase of pulse energy by a factor of 36 with simultaneously reduced intensity noise in the high-frequency range > 100 k H z .

We demonstrate a robust 10-Hz, 1064-nm, all polarization-maintaining (PM) fiber laser front-end for a joule-level solid-state amplification system applying ultrafast optical pulse chopping. A 1064-nm single frequency continuous wave (CW) laser is chopped by an in-line acousto-optic modulator (AOM) to generate ∼7 ns duration pulses at 500-kHz repetition rate, followed by a Sagnac loop (SL) consisting of a 50:50 PM fiber coupler and an electro–optical (EO) phase modulator, which further shortens the pulse duration from 7 ns to 636 ps via a passively fixed optical chopping gate. Finally, the pulse energy is amplified to the sub-µJ level and its repetition rate is further reduced to 10-Hz by another in-line AOM stage. This 10-Hz, 636-ps, sub-µJ level fiber laser realized in an all-PM-fiber configuration can be used as a robust front-end for joule-level solid-state amplification and follow-on nonlinear frequency conversion experiments.