Generation In Photonic Crystal Fiber Research Articles

On the Impact of Wavelength Dependency on Supercontinuum Generation in Photonic Crystal Fibers

It is common practice when simulating propagation through an optical fiber to assume that its characteristic parameters are constant and determined solely by the central wavelength of the input pulse. In this paper, we propose a study of the impact that the actual wavelength dependence of these parameters has on the propagation results. To this end, simulations were carried out considering both the constant model and the wavelength-dependent model, applying them to the case of the especially sensitive effect of supercontinuous generation in a photonic crystal fiber. The results showed differences of up to 20% of the spectrum and, hence, the importance of taking into account the wavelength dependence of the dispersion fiber parameters to obtain more-realistic results in the simulations.

Supercontinuum Generation from Airy-Gaussian Pulses in Photonic Crystal Fiber with Three Zero-Dispersion Points

The supercontinuum generation and manipulation of Airy-Gaussian pulses in a photonic crystal fiber with three zero-dispersion points are studied using the split-step Fourier method. Firstly, the spectral evolution of Airy-Gaussian pulses in four photonic crystal fibers with different barrier widths was discussed, and the optimal fiber was determined after considering the factors of width and flatness. By analyzing the mechanism of supercontinuum generation in photonic crystal fibers with single, double and three zero-dispersion points, it is found that the photonic crystal fiber with three zero-dispersion points have a larger spectral width due to the component of tunneling solitons. Then, the effects of four characteristic parameters (truncation factor a, distribution factor χ0, initial chirp C and central wavelength λ) on forming the supercontinuum spectrum of Airy-Gaussian pulses are analyzed in detail. The results show that the spectral width and energy intensity of the dispersive wave and tunneling soliton generation can be well controlled by adjusting the barrier width and initial parameters of the pulse. These research results provide a theoretical basis for generating and manipulating high-power mid-infrared supercontinuum sources.

Proposal of a novel analytical method for simultaneous ultra-broadband and ultrashort laser pulses generation in photonic crystal fibers with optimized manufacturing process

In this paper, a novel method for simultaneous ultra-broadband and ultrashort femtosecond laser pulse generation in silica photonic crystal fibers is investigated analytically using the fully vectorial effective index method (FVEIM). By reducing the impact of fifth and lower-order dispersions, the method produces narrower laser pulses and wider supercontinuum using a fixed soliton order over a specific distance of the fiber. Additionally, the larger effective areas utilized in this approach make the manufacturing process simpler compared to other samples. These simultaneous features represent the primary innovations of this study.

Flat-top and broadband supercontinuum generation in CCl4-filled circular photonic crystal fiber

In this work, a flat-top and broadband supercontinuum (SC) generation in photonic crystal fibers (PCFs) infiltrated with carbon tetrachloride (CCl[Formula: see text] with different air hole diameters in the cladding has been introduced. The optical properties of the fundamental mode are analyzed by numerical simulation. Based on the obtained results, two optimized PCFs with small dispersion are proposed and verified against SC generation in detail. The first fiber has an all-normal dispersion of [Formula: see text]9.376[Formula: see text]ps.nm[Formula: see text].km[Formula: see text] at the pump wavelength of 0.98[Formula: see text][Formula: see text]m, generating broadband of 768[Formula: see text]nm and flat-top with only 0.3[Formula: see text]nJ of input energy and time duration of 90[Formula: see text]fs. In the meantime the dispersion property of the second fiber is anomalous, which equals 1.105[Formula: see text]ps[Formula: see text][Formula: see text][Formula: see text]nm[Formula: see text][Formula: see text][Formula: see text][Formula: see text]km[Formula: see text] at 1.3[Formula: see text][Formula: see text]m pump wavelength. The second fiber generates a SC spectrum of 1,751.1[Formula: see text]nm with input energy and time duration of 0.55[Formula: see text]nJ and 55[Formula: see text]fs, respectively. Proposed fibers are suitable for all-fiber SC sources which could lead to new low-cost all-fiber optical systems.

Dispersive waves generation in photonic crystal fibers: The role on supercontinuum generation and rogue waves manipulation

Based on photonic crystal fiber, the generation and behavior of dispersive waves in optical fiber system are presented. The individual soliton induced dispersive waves and collision-induced dispersive waves generation are introduced and compared, and the ways of dispersion wave generation are also given in terms of pumping conditions and fiber properties. The dispersion slope affects soliton trapping of dispersive waves and the role of soliton trapping of dispersive waves on supercontinuum is different in photonic crystal fibers with different zero dispersion wavelengths. From the point of view of the number of zero dispersion wavelength, we reveal the effect of dispersive waves on supercontinuum generation and the relationship between dispersive wave and zero dispersion wavelength. Rogue waves induced by dispersive waves are also discussed and how to control rogue waves by using dispersive waves is shown.

High relative-intensity blue light of supercontinuum generation in photonic crystal fibers

A distinct blue peak at 430 nm of the supercontinuum spectrum is generated in 4.6 m photonic crystal fiber with a high air-filling ratio, which is pumped by a 200 ps pulse laser at 1 µm. The amplitude of the blue peak is higher than that of the remaining pump pulse, and the relative intensity blue light of supercontinuum generation is 114%. We have systematically analyzed the formation mechanism and influence factors of the distinct blue peak with different fiber lengths and input pulses. The experimental results show that the wavelength position of the blue peak in the supercontinuum spectrum is almost unchanged, and both the fiber length and pulse width have a great influence on the intensity of the blue peak. In addition, we have discussed the fact that the dynamic changes of the blue peak may be affected by the ∼ 2200 n m peak through cross-phase modulation (XPM). It is possible that the high relative intensity of the blue peak in high-order modes may be originated from the XPM effect and the third-harmonic wave of the fundamental mode.

Numerical Study of High-Order Soliton Generation in Photonic Crystal Fibers: Effect of the Pulse Shape and Its Duration

High-order soliton generation in photonic crystal fibers was simulated using split-step Fourier method (SSFM) and MATLAB. The input pulse shape was studied for various types, super-Gaussian, chirped and pulses obtained from a train of individual Gaussian pulses. The study shows that the order of soliton generated depends on pulse shape, input power and dispersion and nonlinear parameters of the photonic crystal fiber.

Partially coherent UV–VIS light generation in photonic crystal fiber using femtosecond pulses

Light generated in optical fibers due to various nonlinear processes often has a broad spectrum and is commonly considered as a potentially convenient source of seed for tunable wavelength laser systems and many other applications. The nonlinear processes usually considered when discussing this spectrum broadening are coherent.In this paper we present experimental and theoretical investigation of a partially coherent nonlinear phenomenon occurring at the same time — ultraviolet–visible light (375 nm–500 nm) generation in a short photonic crystal fiber pumped by ∼110 fs duration and 1028 nm wavelength pulses.

Numerical simulation of all-normal dispersion visible to near-infrared supercontinuum generation in photonic crystal fibers with core filled chloroform

This study proposes a photonic crystal fiber made of fused silica glass, with the core infiltrated with chloroform as a new source of supercontinuum (SC) spectrum. We numerically study the guiding properties of the fiber structure in terms of characteristic dispersion and mode area of the fundamental mode. Based on the results, we optimized the structural geometries of the CHCl3-core photonic crystal fiber to support the broadband SC generations. The fiber structure with a lattice constant of 1 μm, a filling factor of 0.8, and the diameter of the first-ring air holes equaling 0.5 μm operates in all-normal dispersion. The SC with a broadened spectral bandwidth of 0.64 to 1.80 μm is formed by using a pump pulse with a wavelength of 850 nm, 120 fs duration, and power of 0.833 kW. That fiber would be a good candidate for all-fiber SC sources as cost-effective alternative to glass core fibers.

Investigation of supercontinuum generation in photonic crystal fiber using bursts of femtosecond pulses

Results of experimental and numerical investigation of supercontinuum generation in polarization maintaining photonic crystal fiber using a burst of two orthogonal polarization femtosecond pump pulses are presented. The initial pump pulse source was a mode-locked Yb:KGW laser generating 52 nJ energy 90 fs duration pulses at 1033 nm with 76 MHz repetition rate. Analysis of cross-correlation frequency-resolved optical gating traces and numerical simulation results reveal that there are slight changes in supercontinuum generation when temporal delay between pump pulses in the burst is changed. Weak dependence of supercontinuum characteristics on temporal distance between the pump pulses is related to supercontinuum generation dynamics which is analyzed in detail.

Supercontinuum generation in photonic crystal fibers infiltrated with tetrachloroethylene

This study proposes a photonic crystal fiber made of fused silica glass, with the core infiltrated with tetrachloroethylene (C2Cl4) as a new source of supercontinuum (SC) spectrum. We studied numerically the guiding properties of the several different fiber structures in terms of characteristic dispersion, mode area, and attenuation of the fundamental mode. Based on the results, the structural geometries of three C2Cl4-core photonic crystal fibers were optimized in order to support the broadband SC generations. The first fiber structure with lattice constant 1.5 μm and filling factor 0.4 operates in all-normal dispersion. The SC with a broadened spectral bandwidth of 0.8–2 μm is generated by a pump pulse with a central wavelength of 1.56 μm, 90 fs duration and energy of 1.5 nJ. The second proposed structure, with lattice constant 4.0 μm and filling factor 0.45, performs an anomalous dispersion for wavelengths longer than 1.55 μm. With the same pump pulse as the first fiber, we obtained the coherence SC spectrum in an anomalous dispersion range with wavelength range from 1 to 2 μm. Meanwhile, the third selected fiber (lattice constant 1.5 μm, filling factor 0.55) has two zero dispersion wavelengths at 1.04 μm and 1.82 μm. The octave-spanning of the SC spectrum formed in this fiber was achieved in the wavelength range of 0.7–2.4 μm with an input pulse whose optical properties are 1.03 μm wavelength, 120 fs duration and energy of 2 nJ. Those fibers would be good candidates for all-fiber SC sources as cost-effective alternatives to glass core fibers.

Optimization of the ultra-flattened normal dispersion in photonic crystal fibers infiltrated with olive oil for supercontinuum generation

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

Supercontinuum Generation in Photonic Crystal Fibers Infiltrated with Liquids

In this paper we present the development of a new direction in so-called optofluidics , namely the research of photonic crystal fibers (PCF) infiltrated with liquids. In particular we concentrate on the flagship application of PCF, the process of Supercontinuum Generation (SG), in which injected monochromatic pulse may be dramatically broadened (spectrally), which creates a coherent beam generation of high brightness comparable to that of monochromatic lasers. The supercontinuum is formed when a collection of nonlinear processes act together upon a pump beam in order to cause severe spectral broadening of the original pump beam. Explanation of this process is based on numerical simulations for Generalized Nonlinear Schrödinger equation (GNLSE) which describes the rich nonlinear dynamics of pulse propagation in nonlinear dispersive media. All nonlinear phenomena involved in SG will be analyzed. We present specially activity of the Polish-Vietnamese Group from the beginning in 2016 to recent time in this domain.

Supercontinuum generation in PCF with As2S3/Ge20Sb15Se65 Chalcogenide core pumped at third telecommunication wavelengths for WDM

Chalcogenide-based photonic crystal fibers (PCFs), due to their nonlinear properties, are capable of producing supercontinuum spectra, which can be used in the wavelength division multiplexing (WDM). These types of fibers highly absorb telecommunication wavelengths and hence cannot be used to transmit information over the corresponding wavelengths. We have studied the dispersion engineered chalcogenide PCF numerically, which is important to produce ultra-flat broadband supercontinuum (SC) spectra in all-normal dispersion areas. A 1 mm long, hexagonal chalcogenide PCF made from As2S3/Ge20Sb15Se65 and silica glass pumped at 1550 nm provided a SC bandwidth of 5000 nm with pump power of 1 kW. Here, we have reached zero-dispersion wavelength (ZDW) at third telecommunication window, which in turn has given us a broad spectrum at this window with reasonable efficiency.

Spectral Properties of Photo-Aligned Photonic Crystal Fibers Infiltrated with Gold Nanoparticle-Doped Ferroelectric Liquid Crystals

This paper describes our recent results on light propagation in photonic crystal fibers (PCFs) partially infiltrated with W212 ferroelectric liquid crystal (FLC) doped with 1–3 nm gold nanoparticles (NPs) with a concentration in the range of 0.1–0.5% wt. Based on our previous results devoted to PCFs infiltrated with nematic liquid crystals (NLCs) doped with gold NPs (GNPs), we extend our research line with FLCs doped with these NPs. To enhance the proper alignment of the NP-FLC nanocomposites inside PCFs, we applied an additional photo-aligning layer of SD-1 azo-dye material (DIC, Japan). Electro-optical response times and thermal tuning were studied in detail. We observed an improvement in response times for NP-FLC nanocomposites in comparison to the undoped FLC.

Design and analysis of dispersion-compensating chalcogenide photonic crystal fiber with high birefringence

The photonic crystal fiber (PCF) with a bunch of air holes enclosing the silica core field has momentous and compelling attributes when compared with the ordinary single-mode fibers. In this work, both the birefringence and dispersion properties of a polarization-maintaining chalcogenide (ChG) photonic crystal fiber are numerically investigated by means of the finite element method. Through simulation, it is found that the birefringence of the proposed $${\mathrm{G}\mathrm{e}}_{11.5}{\mathrm{A}\mathrm{s}}_{24}{\mathrm{S}\mathrm{e}}_{64.5}$$ PCF can reach as high as $$0.03$$ when compared with the conventional fiber that has merely $$5\times {10}^{-4}$$ for wavelengths in the 2–10 $$\upmu \mathrm{m}$$ range. The PCF is designed with zero-dispersion wavelengths for x- and y-polarized modes in the 2–10 $$\upmu \mathrm{m}$$ range. It is also observed that over the entire MIR wavelength range, the GVD remains positive and has a maximum value of 30,000 ps2/nm-km. Hence, the proposed $${\mathrm{G}\mathrm{e}}_{11.5}{\mathrm{A}\mathrm{s}}_{24}{\mathrm{S}\mathrm{e}}_{64.5}$$ PCF plays the dual role of acting as a very good polarization-maintaining fiber due to its very high birefringence and an excellent dispersion-compensating fiber due to its large positive GVD. This $${\mathrm{G}\mathrm{e}}_{11.5}{\mathrm{A}\mathrm{s}}_{24}{\mathrm{S}\mathrm{e}}_{64.5}$$ PCF serves as a very good candidate for ultra-broadband high bit-rate transmission. Supercontinuum generation is another important application of PCF. Supercontinuum generation is a generation of coherent and broadband light. SC generation in PCFs has several applications in optical coherence tomography (OCT), optical frequency metrology (OFM), pulse compression, and design of ultrafast femtosecond laser pulses.

Supercontinuum generation in photonic crystal fibers infiltrated with nitrobenzene

A photonic crystal fiber made of fused silica glass and infiltrated with nitrobenzene (C6H5NO2) was proposed as a new nonlinear medium for supercontinuum generation (SG). The guiding properties of the fiber structure were studied numerically, including estimation of the effective refractive index, attenuation, and dispersion of the fundamental mode. Based on the obtained results, three optimized structures were selected and tested numerically for SG. With numerical simulations of nonlinear propagation, we demonstrated the feasibility of spectrally broad and coherent SG in the proposed structures. For the first we obtained a supercontinuum (SC) in the range of 0.8–1.8 µm, for the second in the range of 0.8–2.1 µm, and for the third 1.3–2.3 µm. The pulse energy was in the range of 0.06–0.5 nJ while the pulse duration was 90 fs or 120 fs. For all structures an SC was formed in the first centimeter of the light propagation and conveniently allowed to assume short segments of the fibers. The proposed fibers are good candidates for all-fiber SC sources constituting an attractive alternative to glass-core fibers, since the nonlinearity of nitrobenzene is significantly higher than that of silica. The proposed solution may lead to new low-cost all-fiber optical systems for SG.

Enhanced efficiency of electric field tunability in photonic liquid crystal fibers doped with gold nanoparticles.

In this paper, we present our recent research results on light propagation in photonic crystal fibers (PCFs) infiltrated with a 6CHBT nematic liquid crystal (LC) doped with 2-nm gold nanoparticles (NPs) with a concentration in the range of 0.01 - 0.5% wt. Electro-optical response times and thermal tuning of the investigated samples have been studied in detail. We have observed up to ~80% decrease of rise times for different concentrations of gold NPs in the LC. Moreover, a significant reduction of the Fréedericksz threshold voltage (up to 60%) has been observed for samples with higher concentrations of 2-nm gold NPs in 6CHBT.

All-normal dispersion supercontinuum generation in photonic crystal fibers with large hollow cores infiltrated with toluene

An all-normal dispersion supercontinuum generation in the range of 950 ÷ 1100 nm in photonic crystal fiber with core infiltrated with toluene is reported. The regular lattice hollow core photonic crystal fiber with a large core of 12 μm was designed and developed. The photonic crystal fiber core was selectively filled with toluene. The investigated fiber has normal dispersion in the wavelength range of 0.5 ÷ 2μm, while the absolute value of dispersion varies from 150 to 5 ps/nm/km in the range of 1 ÷ 2µm wavelength. The fiber nonlinear coefficient is 130 W−1km−1 as a result of the trade-off of high nonlinearity of toluene and a large mode area of the fundamental mode. The large mode area is required for the efficient delivery of high power pulses from large mode area input fiber in an all fiber system. As a pump source, a standard subpicosecond fiber laser emitting at 1030 nm with 10nJ pulse energy was used.

Chaotic dynamics and supercontinuum generation with cosh-Gaussian pulses in photonic-crystal fibers

In this paper, we investigate broadband supercontinuum generation in photonic crystal fibers using cosh-Gaussian optical pulses, which provide flatter spectrum than standard Gaussian pulses. This fact can be crucial for telecommunication systems applications. The intensive numerical study of three main telecommunication windows pointed out the most prominent window for spectral broadening. This finding offers the possibility of improving the characteristics of multi-wavelength sources and to enable wavelength density multiplexing systems.