Chalcogenide Suspended-core Fiber Research Articles

Efficient calculation of optical properties of suspended-core fiber via a machine learning algorithm.

Growing nonlinearity demands in mid-infrared applications place more outstanding requirements on fiber structure design. Chalcogenide suspended-core fibers (SCFs) are considered excellent candidates for mid-infrared applications due to their significant advantages in nonlinearity and dispersion management. However, traditional numerical methods for accurate modeling and optimization of SCFs often rely on the performance of computing devices and have many limitations when dealing with complex models. A machine learning algorithm is applied to calculate the optical properties of chalcogenide SCFs, including effective mode area, nonlinear coefficient, and dispersion. The established artificial neural network (ANN) model enables accurate prediction of the above optical properties of As2S3 SCF, for which in the wavelength range of 1.0 to 4.0 µm, the radius of the fiber core is 0.4 to 0.6 µm, and width of the cantilever is 0.06 to 0.09 µm. We demonstrate that this simple ANN model has considerable advantages over the traditional numerical calculation model in computational speed and resource utilization. In summary, the proposed model can quickly provide more accurate optical property predictions, providing a cost-effective solution for precise modeling and optimization of chalcogenide SCFs.

Single-mode suspended large-core chalcohalide fiber with a low zero-dispersion wavelength for supercontinuum generation.

Chalcogenide glass possesses outstanding advantages, such as supercontinuum generation, but its nonlinear applications were limited by large zero-dispersion wavelength (ZDW). Traditional suspended-core fibers can shift the ZDW to near IR with a tiny core size of less than 5 µm but a large evanescent wave loss exists in these fibers. In this paper, we prepared a novel suspended-core fiber (SCF) based on chalcohalide glasses for the first time via the extrusion method, in which the ZDW of the fundamental mode in the fiber with a core size of larger than 30 µm was successfully shifted to 2.6 µm. We also calculated confinement loss (CL) of propagation modes and fundamental mode energy ratio in the fiber. We found that the minimum CL ratio of the high order modes (LP11) to the CL of the fundamental mode is 124, indicating that the single-mode operation condition is satisfied when the wavelength is more than 4.6 µm. The lowest transmission loss is 1.2 dB/m at 6.5 µm. An ultra-broad supercontinuum spectrum, covering from 1.6 to 12 µm was generated in this suspended-core fiber pumped by a 5 µm femtosecond laser. Such a wide SC in the chalcogenide SCF is due to the large core size. All these results demonstrate the potential to use the large core SCF in the application of a mid-IR laser.

Simulation Study of Mid-infrared Supercontinuum Generation at Normal Dispersion Regime in Chalcogenide Suspended-core Fiber Infiltrated with Water

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.

Mid-Infrared Gas Detection Using a Chalcogenide Suspended-Core Fiber

A fast-response mid-infrared gas sensor based on a chalcogenide suspended-core fiber with microchannels fabricated by a tightly focused femtosecond laser pulse was demonstrated. Chalcogenide four-hole suspended-core fiber was fabricated by extrusion and exhibited the lowest transmission loss of 1 dB/m at 4.7 μm. The 50-μm-diameter solid core in the suspended-core fiber was protected by an outside solid jacket to avoid other environmental factors, such as dust and liquid pollution and touch damage. To increase gas filling rate, we introduced microchannels on the side of the suspended-core fiber by femtosecond laser writing to allow gases to enter into the fiber and fully interact with the core. The distribution, shape, and size of the channels could be controlled by laser writing technology. The engineered technique showed the advantage of increased minor loss in the suspended-core fiber. Methane gas sensing utilizing evanescent wave in the core was carried out in the prepared suspended-core fiber with several hundred microchannels. The methane sensitivity was 100 ppm, and the response time was estimated to be less than 20 s.

Numerical investigation on broadband mid-infrared supercontinuum generation in chalcogenide suspended-core fibers**Project supported by the National Nature Science Foundation of China (Grant Nos. 61435003, 61377042, 61505024, and 61421002), Open Fund of State Key Laboratory of Advanced Optical Communication Systems and Networks, China (Grant No. 2015GZKF004), Open Found of Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, China

As2S3 and As2Se3 chalcogenide 3-bridges suspended-core fibers (SCFs) are designed with shifted zero-dispersion wavelengths (ZDWs) at around 1.5 μm, 2 μm, and 2.8 μm, respectively. A generalized nonlinear Schrödinger equation is used to numerically compare supercontinuum (SC) generation in these SCFs pumped at an anomalous dispersion region nearby their ZDWs. Evolutions of the long-wavelength edge (LWE), the power proportion in the long-wavelength region (PPL), and spectral flatness (SF) are calculated and analyzed. Meanwhile, the optimal pump parameters and fiber length are given with LWE, PPL, and SF taken into account. For As2S3 SCFs, SC from a 14 mm-long fiber with a ZDW of 2825 nm pumped at 2870 nm can achieve the longest LWE of and PPL up to ∼72%. For As2Se3 SCFs, the LWE of 15.5 μm and the highest PPL of % can be achieved in a 10 mm-long fiber with ZDW of 1982 nm pumped at 2000 nm. Although the As2Se3 SCFs can achieve much longer LWE than the As2S3 SCFs, the core diameter of As2Se3 SCFs will be much smaller to obtain a similar ZDW, leading to lower damage threshold and output power. Finally, the optimal parameters for generating SC spanning over different mid-IR windows are given.

Structure design and numerical evaluation of highly nonlinear suspended-core chalcogenide fibers

Chalcogenide suspended core fibers are considered as an excellent candidates for several applications in near-and-mid IR applications because of their characteristics of higher linearity and nonlinearity. In this paper, the influence of the fiber structure and host glass on dispersion and nonlinear properties, including the core size and the width of the bridge, especially the shape of the fiber core were analyzed with the finite element method in detail. And then, the optimized structure of SCFs made of As2S3, Ge20Sb5Se75, As2Se3, Ge15As15Se17Te5, which stand for the typical samples of S-based, Se-based and Te-based chalcogenide glasses, have been adopted to get suitable dispersion properties and highest nonlinear optical properties in all kinds of glasses.

Mid-infrared supercontinuum generation in a three-hole Ge 20 Sb 15 Se 65 chalcogenide suspended-core fiber

Abstract This work experimentally demonstrates the supercontinuum (SC) generation in a three-hole arsenic free Ge 20 Sb 15 Se 65 chalcogenide suspended-core fiber. Mechanical drilling was used to prepare the chalcogenide glass preform, which was drawn into suspended-core fibers. The zero-dispersion wavelength of the fiber is moved toward the shorter wavelength of about 3.2 μm through changing the fiber core diameter by controlling the pressure of inert gas during fiber drawing. When a 15 cm-long fiber with a core diameter of 6 μm is pumped using 150 fs pulses at 3.3 μm, SC spanning from ∼3 μm to ∼8 μm was generated.

Supercontinuum generation in three-fold symmetry microstructured fibers in visible and infrared spectral regions

We present a series of three fold symmetric silica microstructured fibers for nonlinear application. The fibers are designed to have zero dispersion wavelength far from the pump wavelength. In our fibers a domination of nonlinear effects is precisely controlled by selectively increased three air holes in the vicinity of the core. Our fibers allow for the broadband single mode spectrum generation and the achievement of flat spectra even after changes of fiber dispersion caused by fabrication inaccuracies. Full Text: PDF References S. T. S?rensen, C. Larsen, C. Jakobsen, C. L. Thomsen, and O. Bang, "Single-mode pumped high air-fill fraction photonic crystal fiber taper for high-power deep-blue supercontinuum sources", Opt. Lett, 39, 1097 (2014). CrossRef V. Couderc, P. Leproux, V. Tombelaine, L. Grossard, and A. Barthélémy, "Raman cascade suppression by using wide band parametric conversion in large normal dispersion regime", Opt. Express, 13, 8584 (2005). CrossRef H. E. Heidepriem, S. C. W. Smith, and T. M. Monro, "Suspended nanowires: Fabrication, design and characterization of fibers with nanoscale cores", Opt. Express, 17, 2646 (2009). CrossRef U. M?ller, Y. Yu, I. Kubat, C. R. Petersen, X. Gai, L. Brilland, D. M´echin, C. Caillaud, J. Troles, B. Davies, and O. Bang, "Multi-milliwatt mid-infrared supercontinuum generation in a suspended core chalcogenide fiber", Opt. Express, 17, 3282 (2015). CrossRef I. Shavrin, S. Novotny, and H. Ludvigsen, "Mode excitation and supercontinuum generation in a few-mode suspended-core fiber", Opt. Express, 21, 32141 (2013). CrossRef M. Klimczak, G. Stepniewski, H. Bookey, A. Szolno, R. Stepien, D. Pysz, A. Kar, A. Waddie, M. R. Taghizadeh, and R. Buczynski, "Broadband infrared supercontinuum generation in hexagonal-lattice tellurite photonic crystal fiber with dispersion optimized for pumping near 1560??nm: reply", Opt. Lett. 39, 2241 (2014). CrossRef X. Zhang, X. Zhu, X. Chen, H. Li, J. Peng, N. Dai, and J. Li, "A hollow beam supercontinuum generation by the supermode superposition in a GeO2 doped triangular-core photonic crystal fiber", Opt. Express, 20, 19799 (2012). CrossRef C. Lesvigne, V. Couderc, A. Tonello, P. Leproux, A. Barthélémy, S. Lacroix, F. Druon, P. Blandin, M. Hanna, and P. Georges, "Visible supercontinuum generation controlled by intermodal four-wave mixing in microstructured fiber", Opt. Lett, 32, 2173 (2007). CrossRef S. T. S?rensen, U. M?ller, C. Larsen, P. M. Moselund, C. Jakobsen, J. Johansen, T. V. Andersen, C. L. Thomsen, and O. Bang, "Deep-blue supercontinnum sources with optimum taper profiles ? verification of GAM", Opt. Express, 20, 10635 (2012). CrossRef A. Kudlinski, M. Lelek, B. Barviau, L. Audry, and A. Mussot, "Efficient blue conversion from a 1064 nm microchip laser in long photonic crystal fiber tapers for fluorescence microscopy", Opt. Express, 18, 16640 (2010). CrossRef A. Kudlinski, G. Bouwmans, O. Vanvincq, Y. Quiquempois, A. Le Rouge, L. Bigot, G. Mélin, and A. Mussot, "White-light cw-pumped supercontinuum generation in highly GeO2 -doped-core photonic crystal fibers", Opt. Lett. 34, 3631 (2009). CrossRef A. Kudlinski, V. Pureur, G. Bouwmans, and A. Mussot, "Experimental investigation of combined four-wave mixing and Raman effect in the normal dispersion regime of a photonic crystal fiber", Opt. Lett. 33, 2488 (2008). CrossRef Z. Holdynski, M. Napierala, P. Mergo, and T. Nasilowski, "Experimental Investigation of Supercontinuum Generation in Photonic Crystal Fibers Pumped With Sub-ns Pulses", J. Lightwave Technol., 33, 2106 (2015). CrossRef U. M?ller, S. T. S?rensen, C. Larsen, P. M. Moselund, C. Jakobsen ,J. Johansen, C. L. Thomsen, O. Bang, "Optimum PCF tapers for blue-enhanced supercontinuum sources", Opt. Fiber Technol., 18, 3104 (2012). CrossRef

Broadband mid-infrared fiber optical parametric oscillator based on a three-hole suspended-core chalcogenide fiber.

A mid-infrared fiber optical parametric oscillator is proposed and designed based on a three-hole As(2)S(5) suspended-core fiber (SCF). The eigenmodes of the SCF are depicted and the pump condition for single-mode operation is analyzed. The zero-dispersion wavelength is shifted to 2 μm by tuning the core diameter of the SCF. Using the degenerate four-wave mixing coupled-wave equations, a tuning range of the idler wavelength from 2 to 5 μm and a maximum conversion efficiency of 19% are numerically predicted in a 0.1-m-long SCF pumped by a 2.7 W thulium-doped fiber laser.

Dispersion Engineering of Highly Nonlinear Chalcogenide Suspended-Core Fibers

Chalcogenide optical fibers are currently undergoing intensive investigation with the aim of exploiting the excellent glass transmission and nonlinear characteristics in the near- and mid-infrared for several applications. Further enhancement of these properties can be obtained, for a particular application, with optical fibers specifically designed that are capable of providing low effective area together with a properly tailored dispersion, matching the characteristics of the laser sources used to excite nonlinear effects. Suspended-core photonic crystal fibers are ideal candidates for nonlinear applications, providing small-core waveguides with large index contrast and tunable dispersion. In this paper, the dispersion properties of As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> suspended-core fibers are numerically analyzed, taking into account, for the first time, all the structural parameters, including the size and the number of the glass bridges. The results show that a proper design of the cladding struts can be exploited to significantly change the fiber properties, altering the maximum value of the dispersion parameter and shifting the zero-dispersion wavelengths over a range of 400 nm.

Multi-milliwatt mid-infrared supercontinuum generation in a suspended core chalcogenide fiber

A low-loss suspended core As(38)Se(62) fiber with core diameter of 4.5 μm and a zero-dispersion wavelength of 3.5 μm was used for mid-infrared supercontinuum generation. The dispersion of the fiber was measured from 2.9 to 4.2 μm and was in good correspondence with the calculated dispersion. An optical parametric amplifier delivering 320 fs pulses with a peak power of 14.8 kW at a repetition rate of 21 MHz was used to pump 18 cm of suspended core fiber at different wavelengths from 3.3 to 4.7 μm. By pumping at 4.4 μm with a peak power of 5.2 kW coupled to the fiber a supercontinuum spanning from 1.7 to 7.5 μm with an average output power of 15.6 mW and an average power >5.0 μm of 4.7 mW was obtained.

Low-threshold Brillouin laser at 2 μm based on suspended-core chalcogenide fiber.

We present, to the best of our knowledge, the first demonstration of a 2 μm Brillouin laser based on a thulium-doped fiber pump and a chalcogenide fiber. A short 1.5 m piece of suspended-core chalcogenide As38Se62 fiber is employed as a gain medium, taking advantage of its small effective mode area and high Brillouin gain coefficient. A record-low lasing threshold of 52 mW is achieved, which is about 10 times lower than previously demonstrated in silica fiber cavities.

Relative intensity noise and frequency noise of a compact Brillouin laser made of As_38Se_62 suspended-core chalcogenide fiber

Relative intensity noise and frequency noise have been measured for the first time for a single-frequency Brillouin chalcogenide As38Se62 fiber laser. This is also the first demonstration of a compact suspended-core fiber Brillouin laser, which exhibits a low threshold power of 22 mW and a slope efficiency of 26% for nonresonant pumping.

Efficient four-wave mixing in an ultra-highly nonlinear suspended-core chalcogenide As_38Se_62 fiber

We report a chalcogenide suspended-core fiber with ultra-high nonlinearity and low attenuation loss. The glass composition is As(38)Se(62).With a core diameter as small as 1.13 µm, a record Kerr nonlinearity of 46,000 W(-1) km(-1) is demonstrated with attenuation loss of 0.9 dB/m. Four-wave mixing is experimented by using a 1m-long chalcogenide fiber for 10 GHz and 42.7 GHz signals. Four-wave mixing efficiencies of -5.6 dB at 10 GHz and -17.5 dB at 42.7 GHz are obtained. We also observed higher orders of four-wave mixing for both repetition rates.

Fourth-order cascaded Raman shift in AsSe chalcogenide suspended-core fiber pumped at 2 μm

Cascaded Raman wavelength shifting up to the fourth order ranging from 2092 to 2450 nm is demonstrated using a nanosecond pump at 1995 nm in a low-loss As(38)Se(62) suspended-core microstructured fiber. These four Stokes shifts are obtained with a low peak power of 11 W, and only 3 W are required to obtain three shifts. The Raman gain coefficient for the fiber is estimated to (1.6±0.5)×10(-11) m/W at 1995 nm. The positions and the amplitudes of the Raman peaks are well reproduced by the numerical simulations of the nonlinear propagation.

Demonstration of Nonlinear Effects in an Ultra-Highly Nonlinear AsSe Suspended-Core Chalcogenide Fiber

Self-phase modulation and 10-GHz four-wave mixing are demonstrated in a low-loss and ultra-highly nonlinear suspended-core chalcogenide fiber. A record Kerr nonlinearity of 31 300 is measured and a direct evidence of fast response in time-resolved measurement of the nonlinear frequency conversion of high repetition rate is provided.

Mechanics of a Particle in a Riemannian Manifold

This work experimentally demonstrates the supercontinuum (SC) generation in a three-hole arsenic free Ge20Sb15Se65 chalcogenide suspended-core fiber. Mechanical drilling was used to prepare the chalcogenide glass preform, which was drawn into suspended-core fibers. The zero-dispersion wavelength of the fiber is moved toward the shorter wavelength of about 3.2 μm through changing the fiber core diameter by controlling the pressure of inert gas during fiber drawing. When a 15 cm-long fiber with a core diameter of 6 μm is pumped using 150 fs pulses at 3.3 μm, SC spanning from ∼3 μm to ∼8 μm was generated.