Towards real-time active imaging of greenhouse gases using tunable mid-infrared all-fiber lasers.

We report a tunable all-fiber laser emitting a maximum output power of 2.55 W around 3240 nm. The fiber laser cavity based on a fluoride fiber doped with dysprosium ions yields an efficiency of 42% according to the in-band launched pump power at 2825 nm.

Recent developments in lanthanide-doped mid-infrared fluoride fiber lasers [Invited].

Mid-infrared fiber sources, emitting between 2.5 µm and 5.0 µm, are interesting for their great potential in several application fields such as material processing, biomedicine, remote sensing and infrared countermeasures due to their high-power, their diffraction-limited beam quality as well as their robust monolithic architecture.

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

We report a 2800 nm -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.

Fuseless side-pump combiner for efficient fluoride-based double-clad fiber pumping.

We report a novel technique for side-pumping fluoride-based double-clad fibers, allowing a record coupling efficiency of 93% and a maximum power handling near 100 W at 981 nm. Our simple technique is based on wrapping a silica taper around a fluoride fiber and, therefore, does not require any complex fusion between these two dissimilar fibers. Under passive cooling, pump combiners made of undoped and erbium-doped fluoride fibers were successfully operated during several hours at respective incident powers of 91 and 44 W.

1.4 W in-band pumped Dy-doped gain-switched fiber laser at 3.24 µm.

In this Letter, we report, to the best of our knowledge, the first demonstration of an in-band pumped gain-switched -doped fiber laser operating at 3.24 µm. The monolithic cavity bounded by two fiber Bragg gratings was pumped by a gain-switched -doped fiber system.

Dual-comb spectroscopy with a phase-modulated probe comb for sub-MHz spectral sampling.

We present a straightforward and efficient method to reduce the mode spacing of a frequency comb based on binary pseudo-random phase modulation of its pulse train. As a proof of concept, we use such a densified comb to perform dual-comb spectroscopy of a long-delay Mach-Zehnder interferometer and a high-quality-factor microresonator with sub-MHz spectral sampling. Since this approach is based on binary phase modulation, it combines all the advantages of other densification techniques: simplicity, single-step implementation, and conservation of the initial comb's power.