We investigate the amplification of nanosecond pulses in a single-mode Er-fluoride fibre amplifier. A PPLN-based optical parametric oscillator (OPO) with a Q-switched Nd:YAG pump laser was used to generate seed pulses at a wavelength of 2790 nm. The OPO system produced seed pulses with sub-10 ns pulse durations and pulse energies of 0.5 μJ at a repetition rate of 10 kHz. These seed pulses were amplified in a single-mode Erbium-fluoride fibre amplifier, consisting of 2.2 m of double-clad fibre with a doping concentration of 7 mol%. Using this setup, we demonstrate gain values of up to 20 dB, output pulse energies of 52.7 μJ, and peak powers of more than 8 kW.
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Funding: This project has received funding from the European Union’s Horizon 2020
research and innovation programme under the Marie Skłodowska-Curie grant
agreement No 843801. This project has received funding from the Engineering
and Physical Sciences Research Council (EPSRC), Grant No. EP/R024898/1.