Mid-Infrared Supercontinuum Generation in Fluoroindate Glass Fibers: History
View Latest Version
Please note this is an old version of this entry, which may differ significantly from the current revision.
Contributor:
Jacek Swiderski

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. The emergence of specialty glass fibers, such as fluoroindate fibers, as well as the advances in fiber-based pulsed oscillators and amplifiers, have accelerated the development of high-power SC systems operating in the mid-infrared spectral band.

  • supercontinuum generation
  • mid-infrared
  • fluoroindate fibers

1. Introduction

Mid-infrared (mid-IR) supercontinuum (SC) generation has attracted considerable interest in recent years, owing to its advantageous applications in many important fields of science and industry. First, this spectral range covers the characteristic absorption lines of several versatile materials and important molecules (e.g., CO2, HCl, CH4, C2H6, O3, NO, and NO2) [1][2], leading to the adoption of mid-IR SC sources for imaging [3], spectroscopy [4][5][6], and remote sensing, including the remote detection of explosives and hazardous chemicals [7][8]. The improvements in these sources have also paved the way toward new possible applications in defense [3][9], utilizing directional infrared countermeasure (DIRCM) systems, where a collimated output beam can be used to blind an infrared detector of a heat-seeking missile [10][11][12]. Finally, their use in medicine (e.g., tissue ablation, coherent anti-Stokes Raman scattering (CARS) microscopy, and breath diagnostics) [13][14][15][16][17][18] as well as in the generation of few-cycle optical pulses in the mid-IR region [19][20][21] or for the stabilization of frequency comb lasers [22] are also worth mentioning. Some of the aforementioned applications require laser sources that deliver high-quality, high-power beams with a broadband and flat spectrum covering the entire 2–5 μm band. Therefore, research on such laser systems providing high spectral brightness, defined as the radiance per unit optical bandwidth, has been the primary focus in many laboratories.
Supercontinuum generation is a phenomenon, first described in the 1970s [23][24], in which high-intensity laser pulses launched into a nonlinear optical medium interact with it, leading to the emission of new light frequencies and, eventually, causing the output spectrum to be much broader than the spectrum of the pump radiation. The efficiency of this process depend on many factors, including the peak power of the irradiated pulses, nonlinearity, dispersion, transmission band, losses, and the interaction length of light with a nonlinear medium. Considering these issues, low-loss optical fibers are preferred for SC generation because they provide effective laser beam confinement in a small fiber core area over its entire length. A schematic of SC generation is shown in Figure 1.
Figure 1. Schematic setup for SC generation.
An SC is usually generated by pumping a nonlinear fiber with high-intensity femtosecond pulses delivered by mode-locked lasers. Spectral broadening of the propagation of light pulses is attributed to a combination of various third-order nonlinear effects, such as self-phase modulation (SPM), cross-phase modulation (XPM), four-wave mixing (FWM), dispersive-wave generation (DWG), and stimulated Raman scattering (SRS) [25]. Although this approach can lead to the generation of a wide continuum, the output power is usually limited to only the milliwatt level. To achieve higher output powers, laser systems that provide picosecond and nanosecond pulse trains with a high average output power must be employed.
The dynamics of process depends on the relationship between the duration of the pump pulse, the emission wavelength of the laser source, and the zero-dispersion wavelength (ZDW) of a nonlinear fiber [26]. When is pumped with femtosecond pulses in the anomalous dispersion region, such that the pump wavelength is longer than the ZDW of the nonlinear material, the spectrum broadening is determined mainly by soliton fission and soliton self-frequency shift (SSFS) [27][28]. By pumping an optical fiber with ultrashort pulses in the normal dispersion region, the SC generation mechanism is dominated by SPM. In the case of SC sources pumped with longer pulses (of the order of picoseconds and nanoseconds) at a wavelength corresponding to the anomalous dispersion regime, the emission of new frequencies is initialized with SPM and modulation instability (MI) [29], manifesting as a disintegration of the long pulses into a distributed spectrum of femtosecond sub-pulses during propagation in the fiber core. In the second step, the ultrafast sub-pulses are red-shifted toward the mid-IR region via soliton dynamics, such as soliton fission and soliton frequency shift, owing to the Raman effect [25][29]. The dominant physical mechanisms underlying SC generation in a fiber pumped with longer pulses in the normal dispersion region are essentially FWM and Raman scattering [29][30].
The choice of a nonlinear material that can be considered for SC generation is determined by a number of parameters, such as the transmission band, nonlinearity, ability to handle high optical power, availability of materials of sufficient quality, and maturity of fiber manufacturing technology that is particularly important, considering practical aspects. To date, silica-based fibers are the predominant nonlinear media for SC generation, mainly owing to their high strength, low losses, high resistance to atmospheric conditions, and above all, their mature drawing technology. Such systems utilizing both passive and active silica fibers have been widely reported over the last decade (see [31][32][33] for examples). However, the longest emission wavelength that can be generated in this medium is ~2.8 μm, which results from the maximum phonon energy of silica glass (1100 cm−1) [34]. The use of silica glass fibers with high-GeO2-doped cores has extended the transmission beyond 3.4 μm [35][36]. However, to extend the spectrum toward the mid-IR further, the use of soft-glass fibers (with wider infrared transmission windows), such as fluoride [37][38][39][40][41][42][43][44][45], tellurite [46][47][48], and chalcogenide (ChG) (e.g., As2S3 and As2Se3) [49][50][51][52][53][54][55] fibers, is mandatory. Each of these media offers certain advantages and disadvantages, such as ease of manufacture, physical strength, wavelength transmission band, corrosion resistance, and thermal damage.
Fluorozirconate (ZBLAN) fibers have been used for SC generation with an average output power of several tens of watts; however, the output spectrum tends to be limited to ~4.7 μm on the long-wavelength side [38][39][41], which results from intrinsic fiber losses at longer wavelengths. Fluoroindate (InF3) fibers with lower phonon energy can guarantee an extended transmission window (to ~5.5 μm [56][57]) and the delivery of high average power output beams [58][59][60][61]. The recent progress in the drawing technology of single-mode tellurite fibers supporting light transmission in a band of ~0.4–5 μm allows considering them theoretically as an alternative to fluoride fibers [46][62][63]. Nevertheless, the current literature reports show that increased material absorption is related to water retention, and, consequently, a reduced damage threshold still hinders the scaling up of the SC power in this medium. Recently, an SC output power of 22.7Wgenerated from a fluotellurite fiber was also demonstrated [64], but in this case, the spectrum long-wavelength edge (LWE) was limited to 3.95 μm. For all aforementioned soft-glass fibers, the LWE of the spectrum is determined by the multiphonon absorption of the nonlinear medium. To achieve emission at wavelengths beyond this edge, short fiber lengths and pumping with high-intensity pulses are required. This approach is typically implemented in a laboratory environment.
Currently, the broadest SC spectra can be generated in ChG fibers with an extremely high nonlinear refractive index n2 that is approximately two orders of magnitude higher than that of fluoride fibers [65]. Although ChG fibers yield an extremely broad mid-IR SC spectrum, even exceeding 10 μm [49][50][66], the overwhelming number of demonstrations to date concern light emission at the milliwatt level. Nonetheless, recent reports on SC generation in As2S3 fibers show that output power scaling up to over 1W with an LWE over 6 μm is possible [67][68]. Further upscaling of average output SC power is also expected, particularly because the damage threshold for arsenic sulfide fibers is rather high, reaching ~2.9 GW/cm2 for 2 ns pulses at 1.9 μm [69] and over 1000 GW/cm2 for 150 fs pulses at 3 μm [70][71].
It is well-known that to achieve efficient spectrum broadening, particularly extending toward the mid-IR region, it is necessary to pump a nonlinear medium in the anomalous dispersion region, relatively close to its ZDW [25][30]. In the case of most available stepindex ChG fibers, the material ZDWs are usually located at wavelengths longer than 4.8 μm that are far away from the emission wavelengths of most available laser sources doped with Er3+, Tm3+, and Ho3+ ions. Consequently, such pumping does not offer optimum broadband SC emission and usually requires the use of complex and expensive optical parametric oscillators (OPOs). In the case of fluoride fibers, the choice of pump sources is wider. Both fluorozirconate and fluoroindate step-index fibers exhibit a ZDW within the wavelength range of ~1.5 to 2.1 μm, covered by the widely available and powerful pulsed laser systems. The advantage of InF3 fibers over ZBLANs is the wider transmission band that renders them ideal candidates for high-power SC generation in the 2–5 μm atmospheric window.

2. Fluoroindate Fibers—Design and Material Properties

Fluoroindate or indium fluoride (InF3) glass fibers have a maximum phonon energy of ~510 cm−1 [72][73] compared with ~579 cm−1 for fluorozirconate glasses [74][75], and thus, they can provide a transmission window with an LWE extended to ~5.5 μm. They also exhibit a higher damage threshold than ChG fibers [73]. Moreover, fluoroindates have a glass transition temperature (Tg) of ~300 °C [76][77]; that is, higher than those of ZBLANs (Tg ~ 260 °C [78][79]) and ChG glasses (Tg ~ 185 °C for As2S3; Tg ~ 178 °C for As2Se3) [80]. The refractive index of these glasses is within the range of 1.47–1.53 [81][82], comparable to that of silicates, indicating that the Fresnel loss is less than 4%. The nonlinear refractive index n2 has been recently determined to be 3.2–4.3 × 10–20 m2/W [83]; that is, 1.5× higher than that for ZBLAN fibers and an advantage in the context of SC generation.
Currently, InF3 glass can be drawn into high-quality optical fibers. There are three commercial manufacturers of single-mode fluoride fibers (Le Verre Fluoré, Thorlabs, and FiberLabs); however, only two offer single-mode InF3 fibers. Figure 2 shows the attenuation curves of InF3 fibers obtained from two different producers as a function of the wavelength. The commercially available fiber offered by Thorlabs exhibits losses < 0.2 dB/m for all wavelengths between ~1.6 and 4.6 µm with a minimum value of ~0.03 dB/m at ~3.6 µm. However, the attenuation of the custom-made fibers could be even lower. For instance, Le Verre Fluoré provides InF3 fibers with losses as low as 0.02 dB/m within the wavelength band of ~1.9–4.1 µm. For all the presented fibers, for wavelengths over 4.8 µm, the material losses significantly increase, reaching more than 0.6 dB/m at 5 µm. The main contribution to absorption is made by the OH− groups at a wavelength of ~2.9 µm [84]. Multiphonon absorption is predominant beyond 4 µm.
Figure 2. Attenuation spectra of selected single-mode fluoroindate fibers (data provided by manufacturers [85][86]).
Another issue addressed in fluoroindate fibers is their mechanical strength, which is much lower than that of silica fibers [87]. Their fragility results from extrinsic defects, such as microcrystals, microbubbles, and core–cladding interface imperfections [88]. However, in recent years, the strength of all fluoride fibers has been significantly improved, allowing the user to stripe, cleave, and even fusion-splice them [42]. Furthermore, to enhance their strength, the fibers can be coated with Kevlar or stainless-steel jackets and connected with different types of connectors (e.g., FC/PC, FC/APC, and SMA-905). Furthermore, InF3 glass fibers have enhanced stability in atmospheric moisture compared with ZBLANs, owing to the lack of the NaF component. Thus, they satisfy the requirements of many industrial applications.
The optimal pump source for SC generation is a mode-locked laser that emits the high peak-power pulses necessary to trigger the nonlinear processes responsible for continuum evolution. Such pulses can be generated directly by single oscillators as well as optical parametric generators (OPGs) and amplifiers. Therefore, it is not surprising that the first demonstration of SC generation in an InF3 fiber was reported using ultrashort laser pulses [89]. This approach exhibits immense potential for broadband mid-IR SC generation in fluoride fibers; however, owing to the pump laser sources used, the output SC power was limited to milliwatts. To achieve a higher output SC power, more powerful pump sources are required. One successful approach is to use a 1.55-μm nanosecond or sub-nanosecond seed laser in tandem with Er3+-doped (or/and Er3+:Yb3+-doped) fiber amplifiers and Tm3+-doped fiber amplifiers (TDFAs) as pump sources [90][91][92]. Such a laser system configuration is commonly known as a master oscillator power amplifier (MOPA) [93][94][95]. In this method, seed pulses (of picosecond or nanosecond duration and the desired wavelength) can be delivered by Q-switched/gain-switched oscillators (including fiber lasers) or pulsed semiconductor lasers. The optical pulses are subsequently amplified to the required peak power level in an appropriately designed one-stage or multi-stage fiber amplifier. Finally, the amplified pulses are launched into a nonlinear medium.

3. Mid-Infrared Supercontinuum Generation Using Fiber MOPA Seeded with 1.55 µm Pulses

This pump setup enables scaling up the average output SC power linearly while maintaining a relatively constant spectral width. This can be achieved by increasing the repetition frequency of the pulses generated by the seed with a simultaneous increase in the average pump power that can be easily realized by providing a suitable gain in the final power amplifier of the MOPA system. Provided that the peak power of the pumping pulses is at the same constant level, the width of the generated SC spectrum should be kept constant. An exemplary setup for SC generation based on a MOPA is shown in Figure 3.
Figure 3. Schematic of the setup for SC generation based on a MOPA seeded with ~1.55 µm pulses. EDFA: erbium-doped fiber amplifier, EYDFA: erbium:ytterbium-doped fiber amplifier, SMF: single-mode (silica) fiber, TDFA: thulium-doped fiber amplifier.
A train of seed pulses is first pre-amplified in an erbium-doped fiber amplifier (EDFA) and erbium:ytterbium-doped fiber amplifier (EYDFA). Subsequently, resulting from MI and Raman scattering, the pulses propagating in a short piece of single-mode standard silica fiber split into shorter sub-pulses and are red-shifted [96], leading to a spectrum spanning from ~1.4 to 2.4 µm. Finally, the spectral components from the ~1.9 to 2.1 µm range are amplified and undergo further SSFS to longer wavelengths in a single-stage or dual-stage TDFA that acts as a nonlinear and active medium. This mechanism is well-described in refs. [97][98][99]. The spectral components from ~1.5–1.85 μm are absorbed by the TDF that acts as an isolator, preventing back-reflection-induced damage to the EDFAs and EYDFA, while wavelengths longer than 1.85 μm are amplified and further red-shifted during propagation through the TDF. In the fluoride fiber, the initially broadened pump radiation is extended further into the mid-infrared region, reaching the LWE theoretically determined by material losses.
Broadband and high spectral flatness SC generation can also be achieved by using ps-scale optical pulses with a central wavelength of ~2 μm. Recently, semiconductor fiber-pigtailed lasers operating at approximately 2 μm have become available that have paved the way for the development of fiber-based MOPA systems. Also 2 µm Q-switched or gain-switched and mode-locked laser systems can be effective pump sources for fluoroindate fibers. The main achievements in this field are summarized in the chart shown in Figure 4, which illustrates the average SC output power increase over the past nine years.
Figure 4. Summary of the most important reports on SC generation (with an LWE of output spectrum beyond 4 μm) in fluoroindate fibers published in the last decade. The bandwidth in the diagram represents the full spectral range (* average output power not revealed; it is supposed to be <100 mW).

Mid-infrared supercontinuum sources have developed rapidly in the last 15 years. The emergence of specialty glass fibers, such as fluoroindate fibers, as well as the advances in fiber-based pulsed oscillators and amplifiers, have accelerated the development of high-power SC systems operating in the spectral range of 2–5 μm. In addition to the output power, the spectral width and flatness of the continuum are important parameters that determine the SC source performance and its usefulness. The first demonstration of SC generation in a fluoroindate fiber was reported by Theberge in 2013 [89]. Since then, much effort has been devoted to improving all the key output parameters of such sources. In less than a decade, the output SC power has been scaled up by more than three orders of magnitude (from less than 10 mW to more than 11 W). Furthermore, interesting pump schemes that enable watt-level SC generation have been proposed. As can be seen in Figure 14, remarkable progress has been made in scaling up the output SC power (illustrated by the increased number of reports as well as increasingly higher output powers), particularly during the last four years. 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. This can be scaled up further if improved thermal management and heat dissipation techniques are implemented. Another vital parameter of mid-IR SC generation is the power distribution toward the red wavelengths. Using optimized nonlinear InF3 fibers and applying suitable pump sources, it was possible to demonstrate an LWE of 5.42 μm for low-power systems (an output power of 8 mW) and 5.1 μm for high-power operation (an output power of 4.06 W). Furthermore, an excellent spectral flatness (5 dB@ 2.0–5.0 µm and 10 dB@ 1.96–4.97 µm) was also achieved. This progress cannot occur without suitable pump sources, particularly those allowing output SC power scaling up. In addition to conventional femtosecond ML laser systems, including optical parametric generation techniques, a spectrum of interesting laser system solutions that provide picosecond and nanosecond pulses has been proposed. It includes fiber-based MOPA systems seeded with semiconductor lasers operating at wavelengths of 1.55 and 2 µm, Q-switched and ML fiber single oscillators, 2-µm fast gain-switched and simultaneous ML fiber lasers and amplifiers, and fiber amplifiers directly seeded with picosecond ML lasers. The InF3 fibers with the lowest attenuation and an appropriate profile of the dispersion curve supported the most efficient red-shifting of the generated SC with an LWE of up to 5.42 µm. There is scope for further spectrum extension, but it would be rather difficult because of the high absorption losses over 5 μm resulting from the multiphonon absorption edge of fluoroindate glasses. 

This entry is adapted from the peer-reviewed paper 10.3390/app12104927

References

  1. Atkins, P.W. The Elements of Physical Chemistry; Oxford University Press: Oxford, UK, 1992.
  2. Henderson-Sapir, O.; Malouf, A.; Bawden, N.; Munch, J.; Jackson, S.D.; Ottaway, D.J. Recent advances in 3.5 μm erbium-doped mid-infrared fiber lasers. IEEE J. Sel. Top. Quantum Electron. 2017, 23, 6–14.
  3. Islam, M.N.; Freeman, M.J.; Peterson, L.M.; Ke, K.; Ifarraguerri, A.; Bailey, C.; Baxley, F.; Wager, M.; Absi, A.; Leonard, J.; et al. Field tests for round-trip imaging at a 1.4 km distance with change detection and ranging using a short-wave infrared supercontinuum laser. Appl. Opt. 2016, 55, 1584–1602.
  4. Borondics, F.; Jossent, M.; Sandt, C.; Lavoute, L.; Gaponov, D.; Hideur, A.; Dumas, P.; Février, S. Supercontinuum-based Fourier transform infrared spectromicroscopy. Optica 2018, 5, 378–381.
  5. Mandon, J.; Sorokin, E.; Sorokina, I.T.; Guelachvili, G.; Picqué, N. Supercontinua for high-resolution absorption multiplex infrared spectroscopy. Opt. Lett. 2008, 33, 285–287.
  6. Lambert-Girard, S.; Allard, M.; Piché, M.; Babin, F. Differential optical absorption spectroscopy lidar for mid-infrared gaseous measurements. Appl. Opt. 2015, 54, 1647–1656.
  7. Jahromi, K.E.; Pan, Q.; Hogstedt, L.; Friis, S.M.M.; Khodabakhsh, A.; Moselund, P.M.; Harren, F.J.M. Mid-infrared supercontinuum-based upconversion detection for trace gas sensing. Opt. Express 2019, 27, 24469–24480.
  8. Walsh, B.M.; Lee, H.R.; Barnes, N.P. Mid infrared lasers for remote sensing applications. J. Lumin. 2016, 169, 400–405.
  9. Kumar, M.; Islam, M.N.; Terry, F.L.; Freeman, M.J.; Chan, A.; Neelakandan, M.; Manzur, T. Stand-off detection of solid targets with diffuse reflection spectroscopy using a high-power mid-infrared supercontinuum source. Appl. Opt. 2012, 51, 2794–2807.
  10. Molocher, B. Countermeasure laser development. In Proceedings of the SPIE 5989, Technologies for Optical Countermeasures II; Femtosecond Phenomena II; and Passive Millimetre-Wave and Terahertz Imaging II, Bruges, Belgium, 26–28 September 2005; Kirkpatrick, S.M., Stoian, R., Titterton, D.H., Appleby, R., Chamberlain, J.M., Krapels, K.A., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2005; p. 598902.
  11. Bekman, H.H.P.T.; van den Heuvel, J.C.; van Putten, F.J.M.; Schleijpen, R. Development of a mid-infrared laser for study of infrared countermeasures techniques. In Proceedings of the SPIE 5615, Technologies for Optical Countermeasures, London, UK, 25–28 October 2004; Titterton, D.H., Ed.; International Society for Optics and Photonics: Bellingham, WA, USA, 2004; pp. 27–38.
  12. Tholl, H.D. Review and prospects of optical countermeasure technologies. In Proceedings of the SPIE 10797, Technologies for Optical Countermeasures XV, Berlin, Germany, 10–13 September 2018; Titterton, D.H., Grasso, R.J., Richardson, M.A., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2018; p. 1079702.
  13. Seddon, A.B. MIR photonics: MIR passive and active fiber-optics chemical and biomedical, sensing and imaging. In Proceedings of the SPIE 9992, Emerging Imaging and Sensing Technologies, Edinburgh, UK, 26–29 September 2016; Lewis, K.L., Hollins, R.C., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2016; p. 999206.
  14. Anderson, R.R.; Farinelli, W.; Laubach, H.; Manstein, D.; Yaroslavsky, A.N.; Gubeli, J., III; Jordan, K.; Neil, G.R.; Shinn, M.; Chandler, W.; et al. Selective photothermolysis of lipid-rich tissues: A free electron laser study. Lasers Surg. Med. 2006, 38, 913–919.
  15. Petersen, C.R.; Prtljaga, N.; Farries, M.; Ward, J.; Napier, B.; Lloyd, G.R.; Nallala, J.; Stone, N.; Bang, O. Mid infrared multispectral tissue imaging using a chalcogenide fiber supercontinuum source. Opt. Lett. 2018, 43, 999–1002.
  16. Labruyere, A.; Tonello, A.; Couderc, V.; Huss, G.; Leproux, P. Compact supercontinuum sources and their biomedical applications. Opt. Fiber Technol. 2012, 18, 375–378.
  17. Kim, S.; Young, C.; Vidakovic, B.; Gabram-Mendola, S.G.A.; Bayer, C.W.; Mizaikoff, B. Potential and challenges for mid-infrared sensors in breath diagnostics. IEEE Sens. J. 2010, 10, 145–158.
  18. Seddon, A.B. Mid-infrared (IR)—A hot topic: The potential for using mid-IR light for non-invasive early detection of skin cancer in vivo. Phys. Status Solidi B 2013, 250, 1020–1027.
  19. Woodward, R.I.; Hudson, D.D.; Fuerbach, A.; Jackson, S.D. Generation of 70-fs pulses at 2.86 μm from a mid-infrared fiber laser. Opt. Lett. 2017, 42, 4893–4896.
  20. Sanari, Y.; Sekiguchi, F.; Nakagawa, K.; Ishii, N.; Kanemitsu, Y.; Hirori, H. Generation of wavelength-tunable few-cycle pulses in the mid-infrared at repetition rates up to 10 kHz. Opt. Lett. 2021, 46, 5280–5283.
  21. Tian, K.; He, L.; Yang, X.; Liang, H. Mid-infrared few-cycle pulse generation and amplification. Photonics 2021, 8, 290.
  22. Hickstein, D.D.; Jung, H.; Carlson, D.R.; Lind, A.; Coddington, I.; Srinivasan, K.; Ycas, G.G.; Cole, D.C.; Kowligy, A.; Fredrick, C.; et al. Ultrabroadband supercontinuum generation and frequency-comb stabilization using on-chip waveguides with both cubic and quadratic nonlinearities. Phys. Rev. Appl. 2017, 8, 014025.
  23. Alfano, R.R.; Shapiro, S.L. Direct distortion of electronic clouds of rare-gas atoms in intense electric fields. Phys. Rev. Lett. 1970, 24, 1217–1220.
  24. Alfano, R.R.; Shapiro, S.L. Observation of self-phase modulation and small-scale filaments in crystals and glasses. Phys. Rev. Lett. 1970, 24, 592–594.
  25. Dudley, J.M.; Taylor, R. (Eds.) Supercontinuum Generation in Optical Fibers; Cambridge University Press (CUP): Cambridge, UK, 2010.
  26. Dudley, J.M.; Genty, G.; Coen, S. Supercontinuum generation in photonic crystal fiber. Rev. Mod. Phys. 2006, 78, 1135–1184.
  27. Husakou, A.V.; Herrmann, J. Supercontinuum generation of higher-order solitons by fission in photonic crystal fibers. Phys. Rev. Lett. 2001, 87, 203901.
  28. Gordon, J.P. Theory of the soliton self-frequency shift. Opt. Lett. 1986, 11, 662–664.
  29. Genty, G.; Coen, S.; Dudley, J.M. Fiber supercontinuum sources. J. Opt. Soc. Am. B 2007, 24, 1771–1785.
  30. Agrawal, G.P. Nonlinear Fiber Optics, 4th ed.; Academic Press: Boston, MA, USA, 2007.
  31. Xia, C.; Kumar, M.; Cheng, M.Y.; Kulkarni, O.P.; Islam, M.N.; Galvanauskas, A.; Terry, F.L.; Freeman, M.J.; Nolan, D.A.; Wood, W.A. Supercontinuum generation in silica fibers by amplified nanosecond laser diode pulses. IEEE J. Sel. Top. Quantum Electron. 2007, 13, 789–797.
  32. Swiderski, J.; Maciejewska, M. Watt-level, all-fiber supercontinuum source based on telecom-grade fiber components. Appl. Phys. B 2012, 109, 177–181.
  33. Romano, C.; Jaouen, Y.; Tench, R.E.; Delavaux, J.-M. Ultra-flat supercontinuum from 1.95 to 2.65 µm in a nanosecond pulsed thulium-doped fiber laser. Opt. Fiber Technol. 2020, 54, 102113.
  34. Lagsgaard, J.; Tu, H. How long wavelengths can one extract from silica-core fibers. Opt. Lett. 2013, 38, 4518–4521.
  35. Yin, K.; Zhang, B.; Yao, J.; Yang, L.; Liu, G.; Hou, J. 1.9–3.6 μm supercontinuum generation in a very short highly nonlinear germania fiber with a high mid-infrared power ratio. Opt. Lett. 2016, 41, 5067–5070.
  36. Jain, D.; Sidharthan, R.; Woyessa, G.; Moselund, P.M.; Bowen, P.; Yoo, S.; Bang, O. Scaling power, bandwidth, and efficiency of mid-infrared supercontinuum source based on a GeO2-doped silica fiber. J. Opt. Soc. Am. B 2019, 36, A86–A92.
  37. Swiderski, J.; Michalska, M.; Grzes, P. Broadband and top-flat mid-infrared supercontinuum generation with 3.52 W time-averaged power in a ZBLAN fiber directly pumped by a 2-µm mode-locked fiber laser and amplifier. Appl. Phys. B 2018, 124, 152.
  38. Yin, K.; Zhang, B.; Yang, L.; Hou, J. 15.2 W spectrally flat all-fiber supercontinuum laser source with >1 W power beyond 3.8 μm. Opt. Lett. 2017, 42, 2334–2337.
  39. Liu, K.; Liu, J.; Shi, H.; Tan, F.; Wang, P. High power mid-infrared supercontinuum generation in a single-mode ZBLAN fiber with up to 21.8 W average output power. Opt. Express 2014, 22, 24384–24391.
  40. Michalska, M.; Hlubina, P.; Swiderski, J. Mid-infrared supercontinuum generation to ~4.7 µm in a ZBLAN fiber pumped by an optical parametric generator. IEEE Photonics J. 2017, 9, 1–7.
  41. Yang, L.; Li, Y.; Zhang, B.; Wu, T.; Zhao, Y.; Hou, J. 30-W supercontinuum generation based on ZBLAN fiber in an all-fiber configuration. Photonics Res. 2019, 7, 1061–1065.
  42. Wu, T.; Yang, L.; Dou, Z.; Yin, K.; He, X.; Zhang, B.; Hou, J. Ultra-efficient, 10-watt-level mid-infrared supercontinuum generation in fluoroindate fiber. Opt. Lett. 2019, 44, 2378–2381.
  43. Grzes, P.; Swiderski, J. Gain-switched 2-µm fiber laser system providing kilowatt peak-power mode-locked resembling pulses and its application to supercontinuum generation in fluoride fibers. IEEE Photonics J. 2018, 10, 1–8.
  44. Xia, C.; Xu, Z.; Islam, M.N.; Terry, J.F.L.; Freeman, M.J.; Zakel, A.; Mauricio, J. 10.5 W time-averaged power mid-IR supercontinuum generation extending beyond 4 µm with direct pulse pattern modulation. IEEE J. Sel. Top. Quantum Electron. 2009, 15, 422–434.
  45. Venck, S.; St-Hilaire, F.; Brilland, L.; Ghosh, A.N.; Chahal, R.; Caillaud, C.; Meneghetti, M.; Troles, J.; Joulain, F.; Cozic, S.; et al. 2–10 µm mid-infrared fiber-based supercontinuum laser source: Experiment and simulation. Laser Photonics Rev. 2020, 14, 2000011.
  46. Thapa, R.; Rhonehouse, D.; Nguyen, D.; Wiersma, K.; Smith, C.; Zong, J.; Chavez-Pirson, A. Mid-IR supercontinuum generation in ultralow loss, dispersion-zero shifted tellurite glass fiber with extended coverage beyond 4.5 µm. In Proceedings of the SPIE 8898, Technologies for Optical Countermeasures X; and High-Power Lasers 2013: Technology and Systems, Dresden, Germany, 23–26 September 2013; Titterton, D.H., Richardson, M.A., Grasso, R.J., Ackermann, H., Bohn, W.L., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2013; p. 889808.
  47. Désévédavy, F.; Gadret, G.; Jules, J.-C.; Kibler, B.; Smektala, F. Supercontinuum generation in tellurite optical fibers. In Springer Series in Materials Science, Technological Advances in Tellurite Glasses; Rivera, V., Manzani, D., Eds.; Springer International Publishing AG: Berlin/Heidelberg, Germany, 2017; Volume 254, pp. 277–299.
  48. Lemiere, A.; Maldonado, A.; Désévédavy, F.; Kibler, B.; Mathey, P.; Gadret, G.; Jules, J.-C.; Hoa, N.P.T.; Suzuki, T.; Ohishi, Y.; et al. Towards absorption spectroscopy by means of mid-infrared supercontinuum generation in a step index tellurite fiber. Laser Phys. 2021, 31, 025702.
  49. Zhang, B.; Yu, Y.; Zhai, C.; Qi, S.; Wang, Y.; Yang, A.; Gai, X.; Wang, R.; Yang, Z.; Luther-Davies, B. High brightness 2.2-12 µm mid-infrared supercontinuum generation in a nontoxic chalcogenide step-index fiber. J. Am. Ceram. Soc. 2016, 99, 2565–2568.
  50. Cheng, T.; Nagasaka, K.; Tuan, T.H.; Xue, X.; Matsumoto, M.; Tezuka, H.; Suzuki, T.; Ohishi, Y. Mid-infrared supercontinuum generation spanning 2.0 to 15.1 µm in a chalcogenide step-index fiber. Opt. Lett. 2016, 41, 2117–2120.
  51. Kedenburg, S.; Steinle, T.; Morz, F.; Steinmann, A.; Giessen, H. High-power mid-infrared high repetition-rate supercontinuum source based on a chalcogenide step-index fiber. Opt. Lett. 2015, 40, 2668–2671.
  52. Wang, Y.; Dai, S. Mid-infrared supercontinuum generation in chalcogenide glass fibers: A brief review. PhotoniX 2021, 2, 9.
  53. Lemiere, A.; Bizot, R.; Désévédavy, F.; Gadret, G.; Jules, J.-C.; Mathey, P.; Aquilina, C.; Béjot, P.; Billard, F.; Faucher, O.; et al. 1.7-18 µm mid-infrared supercontinuum generation in a dispersion engineered step-index chalcogenide fiber. Results Phys. 2021, 26, 104397.
  54. Woyessa, G.; Kwarkye, K.; Dasa, M.K.; Petersen, C.R.; Sidharthan, R.; Chen, S.; Yoo, S.; Bang, O. Power stable 1.5–10.5 µm cascaded mid-infrared supercontinuum laser without thulium amplifier. Opt. Lett. 2021, 46, 1129–1132.
  55. Petersen, C.R.; Moller, U.; Kubat, I.; Zhou, B.; Dupont, S.; Ramsay, J.; Benson, T.; Sujecki, S.; Abdel-Moneim, N.; Tang, Z.; et al. Mid-infrared supercontinuum covering the 1.4-13.3 µm molecular fingerprint region using ultra-high NA chalcogenide step-index fibre. Nat. Photonics 2014, 8, 830–834.
  56. Saad, M. Indium fluoride glass fibres. In Proceedings of the SPIE 8275, Laser Refrigeration of Solids V, San Francisco, CA, USA, 21–26 January 2012; Epstein, R.I., Sheik-Bahae, M., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2012; p. 82750D.
  57. Bei, J.; Monro, T.M.; Hemming, A.; Ebendorff-Heidepriem, H. Reduction of scattering loss in fluoroindate glass fibers. Opt. Mater. Express 2013, 3, 1285–1301.
  58. Gauthier, J.-C.; Fortin, V.; Carrée, J.-Y.; Poulain, S.; Vallée, R.; Bernier, M. Mid-IR supercontinuum from 2.4 to 5.4 µm in a low-loss fluoroindate fiber. Opt. Lett. 2016, 41, 1756–1759.
  59. Théberge, F.; Bérubé, N.; Poulain, S.; Cozic, S.; Robichaud, L.-R.; Bernier, M.; Vallée, R. Watt-level and spectrally flat mid-infrared supercontinuum in fluoroindate fibers. Photon. Res. 2018, 6, 609–613.
  60. Yang, L.; Zhang, B.; Jin, D.; Wu, T.; He, X.; Zhao, Y.; Hou, J. All-fiberized, multi-watt 2-5-µm supercontinuum laser source based on fluoroindate fiber with record conversion efficiency. Opt. Lett. 2018, 43, 5206–5209.
  61. Yang, L.; Zhang, B.; He, X.; Deng, K.; Liu, S.; Hou, J. High-power mid-infrared supercontinuum generation in a fluoroindate fiber with over 2 W power beyond 3.8 µm. Opt. Express 2020, 28, 14973–14979.
  62. Kedenburg, S.; Strutynski, C.; Kibler, B.; Froidevaux, P.; Désévédavy, F.; Gadret, G.; Jules, J.-C.; Steinle, T.; Mörz, F.; Steinmann, A.; et al. High repetition rate mid-infrared supercontinuum generation from 1.3 to 5.3 µm in robust step-index tellurite fibers. J. Opt. Soc. Am. B 2017, 34, 601–607.
  63. Froidevaux, P.; Lemiere, A.; Kibler, B.; Désévédavy, F.; Mathey, P.; Gadret, G.; Jules, J.-C.; Nagasaka, K.; Suzuki, T.; Ohishi, Y.; et al. Dispersion-engineered step-index tellurite fibers for mid-infrared coherent supercontinuum generation from 1.5 to 4.5 µm with sub-nanojoule femtosecond pump pulses. Appl. Sci. 2018, 8, 1875.
  64. Li, Z.; Jia, Z.; Yao, C.; Zhao, Z.; Li, N.; Hu, M.; Ohishi, Y.; Qin, W.; Qin, G. 22.7 W mid-infrared supercontinuum generation in fluorotellurite fibers. Opt. Lett. 2020, 45, 1882–1885.
  65. Sanghera, J.S.; Florea, C.M.; Shaw, L.B.; Pureza, P.; Nquyen, V.Q.; Bashkansky, M.; Dutton, Z.; Aggarwal, I.D. Active and passive chalcogenide glass optical fibers for IR applications: A review. J. Non-Cryst. Solids 2008, 354, 462–467.
  66. Jiao, K.; Yao, J.; Zhao, Z.; Wang, X.; Si, N.; Wang, X.; Chen, P.; Xue, Z.; Tian, Y.; Zhang, B.; et al. Mid-infrared flattened supercontinuum generation in all-normal dispersion tellurium chalcogenide fiber. Opt. Express 2019, 27, 2036–2043.
  67. Martinez, R.A.; Plant, G.; Guo, K.; Janiszewski, B.; Freeman, M.J.; Maynard, R.L.; Islam, M.N.; Terry, F.L.; Alvarez, O.; Chenard, F.; et al. Mid-infrared supercontinuum generation from 1.6 to >11 µm using concatenated step-index fluoride and chalcogenide fibers. Opt. Lett. 2018, 43, 296–299.
  68. Yan, B.; Huang, T.; Zhang, W.; Wang, J.; Yang, L.; Yang, P.; Xia, K.; Bai, S.; Zhao, R.; Wu, D.; et al. Generation of watt-level supercontinuum covering 2-6.5 µm in an all-fiber structured infrared nonlinear transmission system. Opt. Express 2021, 29, 4048–4057.
  69. White, R.T.; Monro, T.M. Cascaded Raman shifting of high-peak-power nanosecond pulses in As2S3 and As2Se3 optical fibers. Opt. Lett. 2011, 36, 2351–2353.
  70. Zhang, Y.; Xu, Y.; You, C.; Xu, D.; Tang, J.; Zhang, P.; Dai, S. Raman gain and femtosecond laser induced damage of Ge-As-S chalcogenide glasses. Opt. Express 2017, 25, 8886–8895.
  71. Zhu, L.; Yang, D.; Wang, L.; Zeng, J.; Zhang, Q.; Xie, M.; Zhang, P.; Dai, S. Optical and thermal stability of Ge-as-Se chalcogenide glasses for femtosecond laser writing. Opt. Mater. 2018, 85, 220–225.
  72. Almeida, R.M.; Pereira, J.C.; Messaddeq, Y.; Aegerter, M.A. Vibrational spectra and structure of fluoroindate glasses. J. Non-Cryst. Solids 1993, 161, 105–108.
  73. Tao, G.; Ebendorff-Heidepriem, H.; Stolyarov, A.M.; Danto, S.; Badding, J.V.; Fink, Y.; Ballato, J.; Abouraddy, A.F. Infrared fibers. Adv. Opt. Photonics 2015, 7, 379–458.
  74. Bartholomew, R.F.; Aitken, B.G.; Newhouse, M.A. Praseodymium-doped cadmium mixed halide glasses for 1.3 µm amplification. J. Non-Cryst. Solids 1995, 184, 229–233.
  75. Fortin, V.; Bernier, M.; Carrier, J.; Vallée, R. Fluoride glass Raman fiber laser at 2185 nm. Opt. Lett. 2011, 36, 4152–4154.
  76. Bei, J.; Monro, T.M.; Hemming, A.; Ebendorff-Heidepriem, H. Reduction of scattering loss in fluoroindate glass fibers. Opt. Mater. Express 2013, 3, 1285–1301.
  77. Saad, M. Fluoride glass fiber: State of the art. In Proceedings of the SPIE 7316, Fiber Optic Sensors and Applications VI, Orlando, FL, USA, 13–17 April 2009; p. 73160N.
  78. Adam, J.-L. Fluoride glass research in France: Fundamentals and applications. J. Fluor. Chem. 2001, 107, 265–270.
  79. France, P.W.; Drexhage, M.G.; Parker, J.M.; Moore, M.W.; Carter, S.F.; Wright, J.V. Fluoride Glass Optical Fibres; CRC Press, Inc.: Boca Raton, FL, USA, 1990.
  80. Shiryaev, V.; Churbanov, M. Trends and prospects for development of chalcogenide fibers for mid-infrared transmission. J. Non-Cryst. Solids 2013, 377, 225–230.
  81. Saad, M. Heavy metal fluoride glass fibers and their applications. In Proceedings of the SPIE 8307, Passive Components and Fiber-Based Devices VIII, Shanghai, China, 13–16 November 2011; Pal, B.P., Ed.; International Society for Optics and Photonics: Bellingham, WA, USA, 2011; p. 83070N.
  82. Soufiane, A.; Gan, F.; L’Helgoualch, H.; Poulain, M. Material dispersion in optimized fluoroindate glasses. J. Non-Cryst. Solids 1995, 184, 36–39.
  83. Basaldua, I.; Kuis, R.; Burkins, P.; Jiang, Z.; Johnson, A.M. Measurements of the nonlinear refractive index (n2) for indium fluoride (InF3) bulk glass and fiber. In Proceedings of the Frontiers in Optics/Laser Science, OSA Technical Digest, Optical Society of America, Paper JTu3A.38, Washington, DC, USA, 16–20 September 2018.
  84. Fedorov, P.P.; Zakalyukin, R.M.; Ignat’eva, L.N.; Bouznik, V.M. Fluoroindate glasses. Russ. Chem. Rev. 2000, 69, 705–716.
  85. Available online: http://leverrefluore.com (accessed on 9 May 2022).
  86. Available online: https://www.thorlabs.com (accessed on 9 May 2022).
  87. Saad, M. Heavy metal fluoride glass fibers and their applications. In Proceedings of the SPIE 8307, Passive Components and Fiber-Based Devices VIII, Shanghai, China, 13–16 November 2011; Pal, B.P., Ed.; International Society for Optics and Photonics: Bellingham, WA, USA, 2011; p. 83070N.
  88. Saad, M. Advances in infrared fibers. In Proceedings of the SPIE 7839, 2nd Workshop on Specialty Optical Fibers and Their Applications (WSOF-2), Oaxaca, Mexico, 13–15 October 2010; Hernández-Cordero, J., Torres-Gómez, I., Méndez, A., Eds.; International Society for Optics and Photonics: Bellingham, WA, USA, 2010; p. 783905.
  89. Théberge, F.; Daigle, J.-F.; Vincent, D.; Mathieu, P.; Fortin, J.; Schmidt, B.E.; Thiré, N.; Légaré, F. Mid-infrared supercontinuum generation in fluoroindate fiber. Opt. Lett. 2013, 38, 4683–4685.
  90. Romano, C.; Jaouen, Y.; Tench, R.E.; Delavaux, J.-M. Ultra-flat supercontinuum from 1.95 to 2.65 µm in a nanosecond pulsed thulium-doped fiber laser. Opt. Fiber Technol. 2020, 54, 102113.
  91. Théberge, F.; Bérubé, N.; Poulain, S.; Cozic, S.; Robichaud, L.-R.; Bernier, M.; Vallée, R. Watt-level and spectrally flat mid-infrared supercontinuum in fluoroindate fibers. Photon. Res. 2018, 6, 609–613.
  92. Swiderski, J.; Michalska, M. Over three-octave spanning supercontinuum generated in a fluoride fiber pumped by Er & Er: Yb-doped and Tm-doped fiber amplifiers. Opt. Laser Technol. 2013, 52, 75–80.
  93. Swiderski, J.; Zajac, A.; Skorczakowski, M. Pulsed ytterbium-doped large mode area double-clad fiber amplifier in MOFPA configuration. Opto-Electron. Rev. 2007, 15, 98–101.
  94. Du, X.; Zhang, H.; Ma, P.; Xiao, H.; Wang, X.; Zhou, P.; Liu, Z. Kilowatt-level fiber amplifier with spectral-broadening-free property, seeded by a random fiber laser. Opt. Lett. 2015, 40, 5311–5314.
  95. Swiderski, J.; Dorosz, D.; Skorczakowski, M.; Pichola, W. Ytterbium-doped fiber amplifier with tunable repetition rate and pulse duration. Laser Phys. 2010, 20, 1–6.
  96. Kudlinski, A.; Mussot, A. Optimization of continuous-wave supercontinuum generation. Opt. Fiber Technol. 2012, 18, 322–326.
  97. Alexander, V.V.; Kulkarni, O.P.; Kumar, M.; Xia, C.; Islam, M.N.; Terry, F.L., Jr.; Welsh, M.J.; Ke, K.; Freeman, M.J.; Neelakandan, M.; et al. Modulation instability initiated high power all-fiber supercontinuum lasers and their applications. Opt. Fiber Technol. 2012, 18, 349–374.
  98. Alexander, V.V.; Shi, Z.; Islam, M.N.; Ke, K.; Freeman, M.J.; Ifarraguerri, A.; Meola, J.; Absi, A.; Leonard, J.; Zadnik, J.; et al. Power scalable > 25 W supercontinuum laser from 2 to 2.5 µm with near-diffraction-limited beam and low output variability. Opt. Lett. 2013, 38, 2292–2294.
  99. Yin, K.; Li, L.; Yao, J.; Zhang, B.; Hou, J. Over 100 W ultra-flat broadband short-wave infrared supercontinuum generation in a thulium-doped fiber amplifier. Opt. Lett. 2015, 40, 4787–4790.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
This entry is offline, you can click here to edit this entry!
Video Production Service
Feedback