We report a numerical study on mid-infrared (IR) supercontinuum (SC) generation in the regime of all normal dispersion using lead bismuth gallate glass photonic crystal fiber. This fiber allows the changing of dispersion from anomalous dispersion to ultra-flat normal dispersion in the wavelength range of over 930 nm by filling its cladding holes with C2Cl4. Using a 12.5 kW laser pulse at 2.8 µm as a pump source, we demonstrate that a broad and highly coherent SC generation spectrum is generated in the wavelength range of 1.2 μ m –3.4 μ m with the effects of vacuum noise. However, pulse-to-pulse relative intensity noise significantly decreases the coherence. These interesting optical properties make the proposed C2Cl4—infiltrated fiber highly promising for various applications in the mid-IR regime, particularly, spectroscopy, optical coherence tomography, and metrology.

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We report simulation results of supercontinuum generation in the suspended-core optical fibers made of chalcogenide (As2S3) infiltrated with water at mid-infrared wavelength range. Applying water-hole instead of the air-hole in fibers allows improving the dispersion characteristics, hence, contributing to supercontinuum generations. As a result, the broadband supercontinuum generation ranging from 1177 nm to 2629 nm was achieved in a 10 cm fiber by utilizing very low input pulse energy of 0.01 nJ and pulse duration of 100 fs at 1920 nm wavelength.

This paper proposes a pure silica photonic crystal fiber (PCF), having its core infiltrated with olive oil, which allows achieving an ultra-flattened normal dispersion regime. As a result, the optimization processes allows us to achieve an ultra-flat normal dispersion in the range of over 682 nm within the wavelength range from 1446 to 2128 nm. Besides, the nonlinear coefficient of the selected PCF structure is extremely high (9.54 x 109 W-1.km-1 at 1550 nm). The proposed PCF structure could be very helpful in investigating the supercontinuum generation which has many potential applications in various promising areas such as spectroscopy, medical diagnostics, etc. Full Text: PDF ReferencesJ.M.Dudley, G.Genty and S.Coen, "Supercontinuum generation in photonic crystal fiber", Rev. Mod. Phys. 78(2006). CrossRef T.Udem, R.Holzwarth and T.W.Hänsch, "Optical frequency metrology", Nature 416 233-7(2002). CrossRef S.Moon and D.Y.Kim, "Ultra-high-speed optical coherence tomography with a stretched pulse supercontinuum source", Opt. Express 14 11575-84 (2006). CrossRef G.P.Agrawal. "Chapter 11 - Highly Nonlinear Fibers", Nonlinear Fiber Optics (Oxford: Academic Press 2013) CrossRef V.R.K. Kumar, A.K. George, J.C. Knight, P.S.J. Russell, "Tellurite photonic crystal fiber", Opt. Exp. 11 2641-2645 (2003). CrossRef R. Buczynski, H. T. Bookey, D. Pysz, R. Stepien, I. Kujawa, J. E. McCarthy, A. J. Waddie, A. K. Kar and M. R. Taghizadeh, "Supercontinuum generation up to 2.5 μm in photonic crystal fiber made of lead-bismuth-galate glass", Laser Phys. Lett.7 666-72 (2010). CrossRef F.G.Omenetto, N.A.Wolchover, M.R. Wehner, M. Ross, A. Efimov, A.J. Taylor, V.V.R.K. Kumar, A.K. George, J.C. Knight, N.Y. Joly, P.St.J. Russell, "Spectrally smooth supercontinuum from 350 nm to 3 µm in sub-centimeter lengths of soft-glass photonic crystal fibers.", Opt. Express 14 4928-4934 (2010). CrossRef H. L.Van, V. C. Long, H. T. Nguyen, A. M. Nguyen, R. Buczyński, R. Kasztelanic, "Application of ethanol infiltration for ultra-flattened normal dispersion in fused silica photonic crystal fibers", Laser Physics, 28 115106 (2018). CrossRef J. Pniewski, T. Stefaniuk, H. L. Van, V. C. Long, L. C. Van, R. Kasztelanic, G. Stępniewski, A. Ramaniuk, M. Trippenbach, and R. Buczynski, "Dispersion engineering in nonlinear soft glass photonic crystal fibers infiltrated with liquids", Appl. Opt. 55, 5033-5040(2016). CrossRef H. D. Quang, J. Pniewski, H. L.Van, R. Aleksandr. V. C. Long, B. Krzysztof, D. X. Khoa, K. Mariusz, and R. Buczynski, "Optimization of optical properties of photonic crystal fibers infiltrated with carbon tetrachloride for supercontinuum generation with subnanojoule femtosecond pulses", Applied Optics, Vol. 57, No. 15, 1559-128X (2018). CrossRef M.Chemnitz,M.Gebhardt, C.Gaida, F.Stutzki, J.Kobelke, J.Limpert, A.Tünnermann and M.A. Schmidt, "Hybrid soliton dynamics in liquid-core fibres", Nat. Commun. 8 42 (2017). CrossRef S.Kedenburg, A.Steinmann, R.Hegenbarth, T.Steinle and H.Giessen, "Nonlinear refractive indices of nonlinear liquids: wavelength dependence and influence of retarded response", Appl. Phys. B 117 803-16 (2014). CrossRef E.Sani and A.Dell'Oro, "Spectral optical constants of ethanol and isopropanol from ultraviolet to far infrared", Opt. Mater. 60 137-41 (2016). CrossRef S.T. Wu, "Absorption measurements of liquid crystals in the ultraviolet, visible, and infrared", J. Appl. Phys. 84 4462-4465 (1998). CrossRef Z. Mousavi, B. Ghafary, M.H. Majles Ara, "Fifth- and third- order nonlinear optical responses of olive oil blended with natural turmeric dye using z-scan technique", Journal of Molecular Liquids, https://doi.org/10.1016/j.molliq.2019.04.077 CrossRef Web page: Refractive Index Info: https://refractiveindex.info. CrossRef I. Bodurov, I. Vlaeva, M. Marudova, T. Yovcheva, K. Nikolova, T. Eftimov, V. Plachkova, "Detection of adulteration in olive oils using optical and thermal methods", Bulgarian Chemical Communications, Volume 45, Special Issue B (pp. 81-85) (2013) DirectLink

A photonic crystal fiber with a hollow core filled with carbon disulfide (CS2) is proposed as a new source of supercontinuum light. We numerically study guiding properties of modeled fibers including the dispersion and the effective mode area of the fundamental mode. As a result, octave spanning of the SC spectrum was achieved in the wavelength range of near-IR from 1.25 μm to 2.3 μm with 90 fs pulse and energy of 1.5 nJ at a pump wavelength of 1.55 μm. The proposed fibers are fully compatible with all-silica fiber systems, in particular, could be used for all-fiber SC sources and new low-cost all-fiber optical systems.