Dispersion Photonic Crystal Fiber Research Articles

Design of large core AS2S3 chalcogenide PCF pumped at all-normal and anomalous dispersion regimes for supercontinuum generation

We design and simulate a near-zero flat dispersion As2S3 photonic crystal fiber (PCF) with a circular shape to generate a broad and smooth supercontinuum (SC). A near-zero flattened dispersion in the all-normal dispersion PCF is maintained in the 4–6.2[Formula: see text]m wavelength range. A 6[Formula: see text]m hyperbolic pulse is injected into this fiber, producing a flat spectrum from 2.45 to 8.4[Formula: see text]m at a peak power of 5[Formula: see text]kW. The generated SC in anomalous dispersion PCF can cover multi-octaves by a pump laser with a 6500[Formula: see text]nm wavelength, 10[Formula: see text]kW of peak power, and a 90[Formula: see text]fs duration in 10[Formula: see text]cm of the proposed fiber structure. These results are achieved by optimizing the fiber structure through the core size. In general, the proposed structures could be used for broadband smooth low-cost SC generation.

Enhancing optical fiber performance through liquid infiltration in photonic crystal fiber

Abstract Liquid infiltration into photonic crystal fibers (PCFs) opens new horizons in optical fiber design. This innovation allows precise control of the refractive index, dispersion, and nonlinear effects within the PCF core, expanding its adaptability for various applications. Through numerical simulations, we explore the impact of different liquids on chromatic dispersion in PCFs, emphasizing the role of filling ratios. Our findings unveil shifts in zero dispersion wavelengths, with chloroform causing significant changes. Lower filling ratios reduce dispersion sensitivity, while higher ratios enable dispersion compensation. This study advances our understanding of liquid-filled PCFs, vital for cutting-edge photonics research and practical applications.

Low-noise supercontinuum generation in chiral all-normal dispersion photonic crystal fibers.

We present the advantages of supercontinuum generation in chiral, therefore circularly birefringent, all-normal dispersion fibers. Due to the absence of nonlinear power transfer between the polarization eigenstates of the fiber, chiral all-normal dispersion fibers do not exhibit any polarization instabilities and thus are an ideal platform for a low-noise supercontinuum generation. By pumping a chiral all-normal dispersion fiber at 802 nm, we obtained an octave-spanning, robustly circularly polarized supercontinuum with a low noise.

A New Design of Ultra-flat Dispersion Photonic Crystal Fiber using Benzene Infiltration

This paper presents new results on dispersion in photonic crystal fibers (PCF) based on a circular lattice, with benzene infiltration into the hollow-core. We achieved near-zero, ultra-flat dispersion through the appropriate adjustment of air hole diameters and pitch of cladding. The result gives a dispersion of ±0.484 ps/nm-1.km over a wavelength range of 450 nm. Besides, we also obtained very high nonlinear coefficients, up to several thousand W–1.km–1, and a very low attenuation, about 10–21 dB/m for optimal structures suitable for supercontinuum generation application.

Dispersion-Oriented Inverse Design of Photonic-Crystal Fiber for Four-Wave Mixing Application

In this paper, we demonstrate the application of a deep learning neural network (DNN) in the dispersion-oriented inverse design of photonic-crystal fiber (PCF) for the fine-tuning of four-wave mixing (FWM). The empirical formula of PCF dispersion is applied instead of numerical simulation to generate a large dataset of phase-matching curves of various PCF designs, which significantly improves the accuracy of the DNN prediction. The accuracies of DNNs’ predicted PCF structure parameters are all above 95%. The simulations of the DNN-predicted PCFs structure demonstrate that the FWM wavelength has an average numerical mean square error (MAE) of 1.92 nm from the design target. With the help of DNN, we designed and fabricated a specific PCF for wavelength conversion via FWM from 1064 nm to 770 nm for biomedical imaging applications. Pumped by a microchip laser at 1064 nm, the signal wavelength is measured at 770.2 nm.

Effect of Some Parameters on Optical Soliton Pulses in Photonic Crystal Fibers

Fiber optics have been greatly enhanced by photonic crystal fibers based on microstructured air-glass designs. On the one hand, such fibers enable very tight light confines in a small mode shape region, resulting in significantly improved alternative options between light and dielectric medium. Photonic crystal fibers, on the other hand, allow light to be guided via air core instead of glass. As a result, the latter form of fiber decreases optical nonlinearities in ways that classic fiber designs cannot. The chirp effect and dispersion of photonic crystal fibers with super-Gaussian pulses during various pulses durations are examined in this paper in both normal and anomalous dispersion patterns. The chirp effect and fiber dispersive nonlinear effects are investigated. For this study, a mathematical model of the solution of a nonlinear equation involved the split-step Fourier method. Peak power was reduced for broad pulses. When the magnitude of the super-Gaussian pulse increased proportionally, pulse constriction was also noticeable, Furthermore, the results reveal that an anomalous dispersion system was superior to a regular dispersion system for pulse . The experimental findings will facilitate further research into more understanding of photonic crystal fibers, and to improve data speeds in modern optical communication systems

Few-cycle all-fiber supercontinuum laser for ultrabroadband multimodal nonlinear microscopy

Temporally coherent supercontinuum sources constitute an attractive alternative to bulk crystal-based sources of few-cycle light pulses. We present a monolithic fiber-optic configuration for generating transform-limited temporally coherent supercontinuum pulses with central wavelength at 1.06 µm and duration as short as 13.0 fs (3.7 optical cycles). The supercontinuum is generated by the action of self-phase modulation and optical wave breaking when pumping an all-normal dispersion photonic crystal fiber with pulses of hundreds of fs duration produced by all-fiber chirped pulsed amplification. Avoidance of free-space propagation between stages confers unequalled robustness, efficiency and cost-effectiveness to this novel configuration. Collectively, the features of all-fiber few-cycle pulsed sources make them powerful tools for applications benefitting from the ultrabroadband spectra and ultrashort pulse durations. Here we exploit these features and the deep penetration of light in biological tissues at the spectral region of 1 µm, to demonstrate their successful performance in ultrabroadband multispectral and multimodal nonlinear microscopy.

Numerical studying of broadband tunable dispersion compensation based on photonic crystal fiber

We propose a broadband tunable negative dispersion photonic crystal fiber (BT-ND-PCF) for dispersion compensation over the S + C + L wavelength bands. BT-ND-PCF is a dual-core structure in which air holes are arranged with a hexagonal lattice and temperature-sensitive liquid is infiltrated into the air holes of the fourth layer. The performance of BT-ND-PCF is numerically analyzed by the finite element method with an anisotropic perfect matching layer. The results show that BT-ND-PCF has a broadband negative dispersion coefficient of −1533.2 to −2836.4 ps / km / nm over the S + C + L wavelength bands, a dispersion coefficient of −2268.9 ps / km / nm at 1550 nm, and a kappa value of 287.9 nm at 1550 nm, which matches with Corning single-mode fiber 28 (SMF). The residual dispersion (RD) after compensating for the dispersion of 1 km SMF is in the range of −0.22 to +0.16 ps / nm. In addition, the dispersion coefficient is changed by 0.679 ps/km/nm per 1°C by controlling the temperature, which is conducive to the accurate compensation of RD. Due to its unique optical properties, BT-ND-PCF can be used in broadband dispersion compensation for dense wavelength division multiplexing optical fiber communication systems.

Theoretical Analysis of The Super-Gaussian Pulse Propagation in Solid-Core Photonic Crystal Fiber

Fiber optics have been greatly enhanced by photonic crystal fibers based on microstructure air-glass designs. On the one hand, such fibers enable highly tight light confine in a small mode shape region, resulting in significantly improved alternative options between light and dielectric medium. Photonic crystal fibers, on the other hand, allow light to be guided via air cores instead of glass. As a result, the latter form of fiber decreases of optical nonlinearities in ways that classic fiber designs cannot. The chirp effect and dispersion of photonic crystal fibers with super-Gaussian pulses during various pulses durations are examined in this paper. In both normal and anomalous dispersion patterns. As done the chirp effect and fiber dispersive nonlinear effects are investigated. For this study, the mathematical model of the solution of nonlinear equation is split-step Fourier method. The peak power reduces for broad pulses. When the magnitude of the super-Gaussian pulse increasing proportion, the pulse constriction is also noticeable, Furthermore, these results disclose important facts, such as the fact that an anomalous dispersion system is superior to a regular dispersion system for pulse. These findings are incredibly useful in learning more about photonic crystal fiber and improving data speeds in modern optical communication systems.

Modeling of lead-bismuth gallate glass ultra-flatted normal dispersion photonic crystal fiber infiltrated with tetrachloroethylene for high coherence mid-infrared supercontinuum generation

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 –3.4 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.

Pulse Shape Estimation in a DSR Fiber Laser Using the Genetic Algorithm

Exploiting the computing power of the genetic algorithm, a numerical study of dissipative soliton resonance (DSR) in a ring laser mode-locked by a real saturable absorber (SA) is conducted. A section of photonic crystal fiber (PCF) is inserted into the laser cavity design to facilitate accurate control of both dispersion and nonlinearity. The influence of the cavity parameters on the evolution of the DSR pulses is systematically analyzed. The genetic algorithm demonstrates that the generation of DSR square pulses depends directly on the PCF dispersion, the PCF nonlinearity, the PCF length, and the modulation depth of the SA. Finally, the sensitivity of the DSR pulse width, peak power and energy to perturbations in a few key design parameters are highlighted.

Fully negative near-zero ultra-flat dispersion photonic crystal fibers in E+S+C+L band

We demonstrate a modified hexagonal three-layer air-hole photonic crystal fiber (PCF) which presents a good ability of dispersion management. The proposed PCF not only achieved an ultra-flattened all-negative dispersion characteristics of 0.15085 ps/(km·nm) fluctuation within the wavelength range of E+S+C+L wavelength band but also has been able to obtain other interesting features such as low confinement loss. Furthermore, the quadrilateral and octagonal structures are investigated to compare the superiority of different structures and analyze why we chose the hexagonal one.

Large negative dispersion in photonic crystal fiber by applying gold nanoparticles in square cladding

In this paper, a new structure of photonic crystal fibers (PCFs) with large negative dispersion is presented in order to compensate the positive dispersion at a wavelength of 1.55 μm. The proposed PCF has square lattice structure. In the basic structure of the cladding, it consists of four square rings, so that each ring has a number of circular holes. In the final proposed structure, the two inner rings of the cladding are reshaped relative to the two outer rings. The first inner ring near the core has stellar shaped holes with gold nanoparticles in its center, and the second inner ring has circular holes with a smaller diameter than the two outer rings. The base material of this fiber is silica. The use of stellar shaped holes with gold nanoparticles cores causes a large amount of negative dispersion, which compensates the positive dispersion. Simulation results show that the minimum dispersion is − 4593 ps/(nm.km) at a wavelength of 1.55 μm which bring a significant improvement compared to other similar references.

Research on the dispersion characteristics of silica-based ring-core photonic crystal fiber used to transmit orbital angular momentum modes

In this paper, based on the silica-based ring-core photonic crystal fiber (PCF) used to transmit orbital angular momentum (OAM) modes, the effects of central air hole and first-layer cladding air holes on the dispersion of ring-core PCF are analyzed. As a result, it is found that the sizes of air holes have a regular regulation effect on the dispersion of PCF. Furthermore, a ring-core PCF which can support 44 OAM modes in communication band is proposed. The characteristics of the designed ring-core PCF, such as number of supported modes, dispersion, nonlinear coefficient and confinement loss, are systematically analyzed by using the finite element method (FEM). In summary, the conclusion is of guiding significance for the design of silica-based ring-core PCF structures, and the designed ring-core PCF has potential applications in the high-capacity fiber communication.

Highly Birefringent, Low Flattened Dispersion Photonic Crystal Fiber in the Terahertz Region

High-performance photonic crystal fiber (PCF) has an important impact on the development of the full potential of complex terahertz systems. A new kind of PCF with D-shaped air holes in core region was proposed for terahertz (THz) region. The numerical simulation results showed that the proposed PCF has a flat dispersion of 0.09 ± 0.28 ps/THz/cm at 0.8-1.2 THz. At 1 THz, an ultra-high birefringence of 0.0595, a low effective material loss (EML) of 0.0557 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and dispersion that can be considered zero were obtained. In addition, other characteristics of the proposed PCF were strictly analyzed, such as confinement loss, bending loss, and effective mode area. The PCF is expected to be used for short distance propagation of terahertz, polarization maintaining and sensing applications of terahertz waves.

Polarization Modulation Instability in Dispersion-Engineered Photonic Crystal Fibers

Generation of widely spaced polarization modulation instability (PMI) sidebands in a wide collection of photonic crystal fibers (PCF), including liquid-filled PCFs, is reported. The contribution of chromatic dispersion and birefringence to the net linear phase mismatch of PMI is investigated in all-normal dispersion PCFs and in PCFs with one (or two) zero dispersion wavelengths. Large frequency shift sidebands are demonstrated experimentally. Suitable fabrication parameters for air-filled and liquid-filled PCFs are proposed as guidelines for the development of dual-wavelength light sources based on PMI.

Dual pump broadband fiber-optic parametric amplifier based on near-zero dispersion photonic crystal fiber with single zero dispersion wavelength

A broadband fiber-optic parametric amplifier (FOPA) based on near-zero dispersion profile with single zero dispersion wavelength (ZDW) by selective liquid infiltration technique is numerically investigated. Here, the gain and bandwidth for an FOPA incorporating “dual pumping” scheme are thoroughly investigated by varying the fiber length, operating wavelength (central wavelength), and pump power. The structure is engineered in such a way that the dispersion profile is having near-zero dispersion value (negative β2) for a wide wavelength range and small positive β4 around the pump wavelength; thereby, the phase mismatch term remains within the favorable value for a wide wavelength leading to wider FOPA sources. The structure also supports reasonable high nonlinearity and low propagation loss. Our numerical investigation results in an FOPA with optimized bandwidth of around 180 nm close to communication wavelength. Finally, a detailed comparative study of the single pump scheme and dual pump scheme for FOPA/amplifier gain and spectrum bandwidth has been performed for identical fiber parameters. It has been observed that dual pump scheme provides smoother/flatter spectrum (lesser gain fluctuation) around the center of the optimized profile with slightly lesser bandwidth compared to single pump operation. Additionally, it was observed that the dual pump FOPA supports higher pump power thereby enabling higher FOPA unaltered peak gain (3 dB) throughout the bandwidth (the peak and dip of the gain spectrum difference remaining within 3 dB) than that of single pump scheme.

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

Structure parameter effects of PCF on dispersion for singlemode regime based on V-parameter

In this paper, the dispersion of photonic crystal fiber (PCF) with five rings hexagonal geometry have investigated by varying different parameters. Many researchers had used small size of fiber ( small pitch distance) to ensure the single mode operation but decreasing the pitch distance leads to increasing the dispersion. It is important to get suitable pitch distance so that it is not large to avoid the multimode operation and not small to avoid high dispersion. In this work, this condition has obtained depended on V-parameter. We have estimated the V-parameter by using the step-index fiber approximation. The Pitch distance which has been obtained is 5 um with low dispersion and low V-parameter ≤ 2.405 (single mode operation). In addition, to get more low dispersion and V-parameter, a doping with two different value of Ge ( 4.1% and 7%) has been applied in core.

Low noise all-fiber amplification of a coherent supercontinuum at 2 \xb5m and its limits imposed by polarization noise

We report a low noise, broadband, ultrafast Thulium/Holmium co-doped all-fiber chirped pulse amplifier, seeded by an Erbium-fiber system spectrally broadened via coherent supercontinuum generation in an all-normal dispersion photonic crystal fiber. The amplifier supports a − 20 dB bandwidth of more than 300 nm and delivers high quality 66 fs pulses with more than 70 kW peak power directly from the output fiber. The total relative intensity noise (RIN) integrated from 10 Hz to 20 MHz is 0.07%, which to our knowledge is the lowest reported RIN for wideband ultrafast amplifiers operating at 2 µm to date. This is achieved by eliminating noise-sensitive anomalous dispersion nonlinear dynamics from the spectral broadening stage. In addition, we identify the origin of the remaining excess RIN as polarization modulational instability (PMI), and propose a route towards complete elimination of this excess noise. Hence, our work paves the way for a next generation of ultra-low noise frequency combs and ultrashort pulse sources in the 2 µm spectral region that rival or even outperform the excellent noise characteristics of Erbium-fiber technology.