10-Hz, 636-ps, 1064-nm, all polarization-maintaining fiber front-end based on ultrafast optical fiber pulse chopping

Abstract

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.