Dual stage fiber amplifier operating near 3  µm with milijoule-level, sub-ns pulses at 5  W

Abstract

We report a 2800 nm E r 3 + -doped fluoride fiber amplifier that delivers 1 mJ pulses with an average power of 5 W and pulse duration of 1 ns at 5 kHz repetition rate. To the best of our knowledge, this is the highest pulse energy achieved from a fluoride-fiber-based system operating near 3 µm, and the W-level average power and short pulse lengths make the system a promising tool for biomaterials processing.

Amplification of Nanosecond Pulses in a Single- Mode Erbium-Doped Fluoride Fibre Amplifier

“…The optical-to-optical efficiency reached a value of 9 %this included Fresnel reflection losses of approximately 10 % at the uncoated AlF 3 end-cap facet and the uncoated CaF 2 collimating lens. This efficiency value is in good agreement with previously reported results [9], [12].…”

“…Comparing the output power per fibre core area with previously published setups shows an increase of almost one order of magnitude. We have achieved a value of 279 kW/cm 2 versus values of 41 kW/cm 2 , 32 kW/cm 2 , and 49 kW/cm 2 in references [9], [11], and [12], respectively. Building upon these results, further work will focus on power scaling, addition of amplifier stages, and improvements of amplifier efficiency.…”

“…Du et al [11] have demonstrated a multimode Erfluoride fibre amplifier with output pulse energies of 670 µJ and pulse durations of 10 ns at a low repetition rate of 10 Hz. Most recently, Aydin et al [12] have demonstrated a dualstage, multimode MOPA system with output pulse energies of 1 mJ, 5 kHz repetition rate, and pulse durations of 1 ns.…”

Amplification of GaSb-Based Diode Lasers in an Erbium-Doped Fluoride Fibre Amplifier

“…Output powers of up to 40 W have been achieved from Er-doped fluoride fibre lasers, operating at wavelengths around 2.8 µm [18]. Several fluoride fibre amplifier systems have been demonstrated, including the amplification of femtosecond pulses from a mode-locked fibre laser [19], picosecond pulses from optical parametric generator systems [20], [21], [22], and nanosecond pulses from optical parametric oscillators [23], [24], [25].…”

Wavelength-Tuning of Nanosecond Pulses in Er-Doped Fluoride Fibre Amplifier

“…More recently, several groups have demonstrated Er-doped fluoride fibre amplifiers for further power scaling of laser systems in the MIR. This included the generation of supercontinuum by amplification of picosecond pulses in a single-mode fibre amplifier at 2750 nm [13], the amplification of nanosecond pulses in a multi-mode fibre amplifier at 2710 nm [14], the amplification of 50 µJ pulses in a single-mode fibre amplifier at 2790 nm [15], and the demonstration of millijoule pulse energies from a dualstage, multi-mode fibre amplifier at 2790 nm [16].…”