Fibre lasers in the mid-infrared regime are useful for a diverse range of fields, including chemical and biomedical sensing, military applications and materials processing. This Review summarizes the different rare-earth cations and host materials used in mid-infrared fibre laser technology, and discusses the future applications and challenges for the field.

Towards high-power mid-infrared emission from a fibre laser

http://www.epa.gov/oppfead1/labeling/lrm/ individual chapters of the Pesticide Label Review Manual, 3rd Edition Pesticide Label Review Manual, 3rd Edition. Utilized by the EPA Office of Pesticide Programs (OPP) to improve the quality and consistency of pesticide labels. This document provides guidance on how the US EPA interprets the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and its specific requirements for label language and format. Chapters include: • Precautionary labeling (including Signal Word, Personal Protective Equipment, and First Aid Statements) • Physical or Chemical Hazards • Worker Protection Labeling • Directions for Use • Labeling Claims • Storage and Disposal • Identification numbers (including EPA registration number)

Appendix A: informational sources on pesticides and health.

Frequency down-conversion of solid-state laser sources to the mid-infrared spectral range using non-oxide nonlinear crystals

Fiber lasers have seen progressive developments in terms of spectral coverage and linewidth, output power, pulse energy, and ultrashort pulse width since the first demonstration of a glass fiber laser in 1964. Their applications have extended into a variety of fields accordingly. In this paper, the milestones of glass fiber laser development are briefly reviewed and recent advances of high-power continuous wave, Q-switched, mode-locked, and single-frequency fiber lasers in the 1, 1.5, 2, and 3 μm regions and their applications in such areas as industry, medicine, research, defense, and security are addressed in detail.

Fiber lasers and their applications [Invited]

With continued steep growth in the volume of data transmitted over optical networks there is a widely recognized need for more sophisticated photonics technologies to forestall a ‘capacity crunch’[1]. A promising solution is to open new spectral regions at wavelengths near 2µm and to exploit the long-wavelength transmission and amplification capabilities of hollowcore photonic-bandgap fibres[2,3] and the recently available thulium-doped fibre amplifiers[4]. To date, photodetector devices for this window have largely relied on III-V materials[5] or, where the benefits of integration with silicon photonics are sought, GeSn alloys, which have been demonstrated thus far with only limited utility[6-9]. Here, we describe a silicon photodiode operating at 20 Gb/s in this wavelength region. The detector is compatible with standard silicon processing and is integrated directly with silicon-on-insulator waveguides, which suggests future utility in silicon-based mid-infrared integrated optics for applications in communications.

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High-speed detection at two micrometres with monolithic silicon photodiodes

We present the first in-band diode-pumped TDFAs operating in the 2µm wavelength region and test their suitability as high performance amplifiers in potential future telecommunication networks. We demonstrate amplification over a 240nm wide window in the range 1810 - 2050nm with up to 36dB gain and noise figure as low as 4.5dB.

Diode-pumped wideband thulium-doped fiber amplifiers for optical communications in the 1800 - 2050 nm window.

We present a tunable, high power cladding-pumped holmium doped fiber laser. The laser generated >15 W CW average power across a wavelength range of 2.043 – 2.171 μm, with a maximum output power of 29.7 W at 2.120 μm. The laser also produced 18.2 W when operating at 2.171 µm. To the best of our knowledge this is the highest power operation of a holmium doped laser at a wavelength >2.15 µm. We discuss the significance of background losses and fiber design for achieving efficient operation in holmium doped fibers.

A cladding-pumped, tunable holmium doped fiber laser

We have demonstrated the highest reported output power from a mid-IR ZGP OPO. The laser is a cascaded hybrid system consisting of a thulium fibre laser, Ho:YAG solid state laser and a Zinc Germanium Phosphide parametric oscillator. The system produces 27 W of output power in the 3-5 μm wavelength range with an M2 = 4.0 when operating in a repetitively q-switched mode, and a modulated peak output power of 99 W at a reduced duty cycle of 25%.

99 W mid-IR operation of a ZGP OPO at 25% duty cycle

A review of recent progress in holmium-doped silica fibre sources

We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

Nikita Simakov

Papers

Diode-pumped wideband thulium-doped fiber amplifiers for optical communications in the 1800 - 2050 nm window.

A cladding-pumped, tunable holmium doped fiber laser

99 W mid-IR operation of a ZGP OPO at 25% duty cycle

A review of recent progress in holmium-doped silica fibre sources

High power operation of cladding pumped holmium-doped silica fibre lasers