# Recent Development of Mid-Infrared Supercontinuum Generation in Fluoroindate Glass Fibers
## 8 Summary and Outlook
Low-power mid-IR SC sources, pumped by OPCs, have rather low output power stability, which directly results from the poor stability of pumping pulses. The power stability of high-power InF3-based SC sources is determined by the power stability of fiber-based pump laser systems. The Q-switched Tm-doped fiber lasers [122] and gain-switched Tm-doped fiber lasers and amplifiers [123] provide output pulses with quite high fluctuations of amplitude, and consequently, it can be assumed that the output SC power is not very stable. The fiber-based MOPAs seeded with semiconductor lasers, or mode-locked fiber lasers seem to provide better power stability over a long period of operation. In particular, all-fiber systems, where the output of the pump MOPA system is fusion spliced to a fluoroindate fiber, can improve the thermal management, conversion efficiency, and can offer an excellent SC source operation. Recently, [PERSON] et al. reported an SC laser system tested for over 12 min at an output power of 10.17 W, showing a highly stable output beam with RMS of the SC power of 0.33% [42]. Based on the presented results, this concept seems to be the best for practical applications. Fourth, further improvements in the performance of SC sources should pave the way for new applications in both academia and the industry (e.g., spectroscopy and medicine). An extensive review of the most promising practical realizations of supercontinuum systems, including the diversity of pump configurations, is presented. It is shown that different pump system configurations delivering femtosecond, picosecond, and nanosecond optical pulses combined with a low-loss InF3 fiber can support efficient supercontinuum generation with a spectrum covering the entire 2-5 \(\upmu\)m spectral band. High-power SC configurations, of which the most powerful one emits an average output power of 11.8 W, are focused on in this study. The review indicates that the potential of fluoroindate fibers has not been fully explored yet, and there is still scope for further improvement in their performance, particularly in high-power SC systems. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline \multirow{2}{*}{**Pump Source Architecture**} & **Pump Parameters** & **InF3 Fiber Parameters** & **SC Parameters** & **(Average** & **Ref.** \\  & **Width/PRF/Wavelength/ Average Power** & **Diameter/NA/Fiber Length** & **Flatness)** & **Ref.** \\ \hline OPG & 70 fs/INP/3.4 \(\upmu\)m/INP & 16 \(\upmu\)m/0.14/9.5 m & INP/4.95 \(\upmu\)m/20 [EMAIL_ADDRESS]–4.7 \(\upmu\)m & [101] \\ \hline MOPA: MLFL (seed), 1 \(\times\) EDFA, 1 \(\times\) TDFA & 97.5 fs/50 MHz/1.55 \(\upmu\)m/0.57 W & 7 \(\upmu\)m/0.26/0.55 m & 247 mW/-5 \(\upmu\)m/INP & [102] \\ \hline MOPA: OPG (seed), 2.75 \(\upmu\)m/INP & 400 ps/2 kHz/2.75 \(\upmu\)m/INP & 13.5 \(\upmu\)m/0.3/15 m & 8 mW/5.42 \(\upmu\)m/20 [EMAIL_ADDRESS]–5.4 \(\upmu\)m & [104] \\ \hline OPG & 70 ps/1 kHz/2.02 \(\upmu\)m/INP & 9 \(\upmu\)m/0.26/9 m & INP/5.25 \(\upmu\)m/5 [EMAIL_ADDRESS]–5.0 \(\upmu\)m & [103] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of key results of and setups for SC generation in fluoroindate fibers (OPG—optical parametric generator; MOPA—master oscillator power amplifier; DFB—distributed feedback; EDFA—erbium-doped fiber amplifier; EDFA—erbium->iterbium->iterbium->doped fiber amplifier; TDFA—thuliump->-doped fiber amplifier; MLFL—mode-locked fiber laser; DM—discrete mode; QML—Q-switched and mode-locked; GSML—gain-switched and mode-locked; PRF—pulse repetition frequency; LWE—long-wavelength edge; INF—information not provided).