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Supercontinuum (SC) generation that leads to the emission of broadband radiation has been extensively studied. In particular, SC sources encompassing the wavelength range of 2–5 μm have attracted considerable interest in the last decade, and a continuous increase in the output power and spectrum width has been observed. To enable broadband and high-power SC generation, suitable nonlinear media combined with appropriate pump sources must be used, maintaining the output as spectrally flat. This paper briefly reviews the current state-of-the-art SC sources restricted to those based on fluoroindate fibers, including systems pumped with femtosecond, picosecond, and nanosecond pulses. First, the concept of SC generation in optical fibers is briefly presented. This is followed by an examination of indium fluoride optical fibers, with an emphasis on their material and waveguide properties. Furthermore, the advances in SC generation in fluoroindate fibers, including the latest results on high-power (Watt-level) continuum generation adopting different pump schemes, are also explored. A record time-averaged output power of 11.8 W with a spectrum spanning from ~1.9 to 4.9 µm has been demonstrated, which is certainly not the power limit of this technology. Finally, potential future directions of research are discussed at the end of this paper. [ABSTRACT FROM AUTHOR]

Mid-infrared (mid-IR) supercontinuum (SC) sources have recently gained much interest, as a key technology for such applications as spectral molecular fingerprinting, laser surgery, and infrared counter measures. However, one of the challenges facing this technology is how to obtain high power and broadband light covering a spectral band of at least 2–5 µm, especially with a very efficient output power distribution towards the mid-IR region. This directly affects their usage in the practical applications mentioned above. Typically, an SC is generated by pumping a piece of nonlinear fibre with high-intensity femtosecond pulses provided by mode-locked lasers. Although this approach can lead to wide continuum generation, the output power is limited only to the milliWatt level. Therefore, to achieve high-power SC light, other laser systems need to be employed as pump sources. This paper briefly reviews SC sources, restricted to those with an average output power of over 0.4 W and simultaneously with a long-wavelength edge of the continuum spectrum of over 2.4 µm. Firstly, the concepts of SC generation, including the nonlinear phenomena governing this process and the most relevant mid-IR fibre materials, are presented. Following this study, a review of the main results on SC generation in silica and soft-glass fibres, also including my experimental results, is presented. Emphasis is given to high-power SC generation with the use of different pump schemes, providing an efficient power distribution towards longer wavelengths. Some discussion and prospective predictions are proposed at the end of the paper. [ABSTRACT FROM AUTHOR]

We demonstrate broadband 0.9–3.6µm supercontinuum (SC) generation with 0.66W of output power, using a single-mode fluoride (ZBLAN) fiber pumped by 1.55µm nanosecond pulses amplified in a cascade of fiber amplifiers. Expanding the pump source by adding an additional amplification section based on thulium-doped fibers, the long-wavelength edge of the spectrum was shifted to ~4µm and was limited by intrinsic losses of the used nonlinear fiber. For this cases, the average SC power as high as 288mW was recorded, of which 266mW (92%), 167mW (58%) and 60mW (21%) corresponds to wavelengths longer than 2μm, 3μm and 3.6μm. The performance of the SC sources is described. [ABSTRACT FROM AUTHOR]

Highlights: [•] An all-fiber, silica-based supercontinuum source was developed. [•] Over 2.3W in the spectral band of ∼(1.7–2.7) μm was recorded. [•] 10dB spectral flatness from 1.95 to 2.52μm (span of 570nm) was demonstrated. [•] Tm-doped single-mode silica fibers were utilized as nonlinear and amplification media. [ABSTRACT FROM AUTHOR]