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Yushan Yan - One of the best experts on this subject based on the ideXlab platform.
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Pure Silica zeolite thin films by vapor phase transport of fluoride for low k applications
Microporous and Mesoporous Materials, 2010Co-Authors: Heather K Hunt, Yushan Yan, Christopher M Lew, Minwei Sun, Mark E DavisAbstract:A new method to synthesize Pure-Silica zeolite films is presented. Specifically, this method uses fluoridemediated syntheses that involve the vapor phase transport of the mineralizing agent, fluoride, to crystallize a precursor film deposited by dip-coating techniques to obtain thin films of Pure-Silica zeolites with LTA, CHA, and ITW topologies. The films are characterized by a combination of X-ray diffraction, field emission scanning electron microscopy, and X-ray energy dispersive analyses. The films are polycrystalline, intergrown, continuous and well-adhered to their substrates. The usefulness of these thin films as low-k materials, that are needed to reduce cross-talk noise and energy dissipation between transistors in an integrated circuit, is demonstrated via evaluation of the Pure-Silica LTA film. The LTA topology has the lowest framework density (FD = 14.2) of the 19 known Pure-Silica zeolites, and theoretically could have the lowest dielectric constant. The average dielectric constants of the LTA films are calculated from capacitance measurements at a frequency of 1 MHz with metal–insulator–metal structures on lowresistivity silicon substrates, and yield an average k = 1.69, well within the ultra low-k material requirements (k between 2.3 and 2.6).
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on wafer crystallization of ultralow κ Pure Silica zeolite films
Angewandte Chemie, 2009Co-Authors: Yan Liu, Christopher M Lew, Minwei Sun, Rui Cai, Junlan Wang, Grant M Kloster, Boyan Boyanov, Yushan YanAbstract:A higher goal: An on-wafer crystallization process to prepare Pure Silica zeolite (PSZ) MEL-type films that is superior to the previously used hydrothermal process is reported. These striation-free MEL-type films (right, see picture) outperform the traditional spin-on films (left) in terms of the kappa value, mechanical properties, surface roughness, mesopore size, and size distribution.
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Pure Silica zeolite mfi and mel low dielectric constant films with fluoro organic functionalization
Advanced Functional Materials, 2008Co-Authors: Christopher M Lew, Mark E Davis, Dora I Medina, Minwei Sun, Yan Liu, Junlan Wang, Sonjong Hwang, Yushan YanAbstract:The synthesis of organic-functionalized Pure-Silica-zeolites (PSZs) with MFI- and MEL-type structures for low-k applications prepared through a direct-synthesis method by adding a fluorinated silane to the synthesis solution is reported. The added fluorine functionality increases the hydrophobicity of the zeolites, which are characterized by scanning electron microscopy, X-ray diffraction, 29Si and 19F solid-state NMR spectroscopy, nitrogen adsorption, and thermogravimetric analysis. The functionalized zeolite powders have low water content and calcined spin-on films prepared from the functionalized nanoparticle suspensions exhibit higher water contact angles and lower k values (2.1 and 1.8 for the functionalized MFI- and MEL-type zeolites, respectively) than PSZ films. The use of a direct-synthesis method to decrease the moisture adsorption in the films eliminates the extra post-spin-on silylation steps that are traditionally used to render the zeolite films hydrophobic.
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mel type Pure Silica zeolite nanocrystals prepared by an evaporation assisted two stage synthesis method as ultra low k materials
Advanced Functional Materials, 2008Co-Authors: Yan Liu, Minwei Sun, Christopher M Lew, Junlan Wang, Yushan YanAbstract:A MEL-type Pure-Silica zeolite (PSZ), prepared by spin-on of nanoparticle suspensions, has been shown to be a promising ultra-low-dielectric-constant (k) material because of its high mechanical strength, hydrophobicity, and chemical stability. In our previous works, a two-stage synthesis method was used to synthesize a MEL-zeolite nanoparticle suspension, in which both nanocrystal yield and particle size of the zeolite suspension increased with increasing synthesis time. For instance, at a crystal yield of 63%, the particle size is 80 nm, which has proved to be too large because it introduces a number of problems for the spin-on films, including large surface roughness, surface striations, and large mesopores. In the current study, the two-stage synthesis method is modified into an evaporation-assisted two-stage method by adding a solvent-evaporation process between the two thermal-treatment steps. The modified method can yield much smaller particle sizes (e.g., 14 vs. 80 nm) while maintaining the same nanocrystal yields as the two-stage synthesis. Furthermore, the nanoparticle suspensions from the evaporation-assisted two-stage synthesis show a bimodal particle size distribution. The primary nanoparticles are around 14 nm in size and are stable in the final suspension with 60% solvent evaporation. The factors that affect nanocrystal synthesis are discussed, including the concentration, pH value, and viscosity. Spin-on films prepared by using suspensions synthesized this way have no striations and improved elastic modulus (9.67 ± 1.48 GPa vs. 7.82 ± 1.30 GPa), as well as a similar k value (1.91 ± 0.09 vs. 1.89 ± 0.08) to the previous two-stage synthesized films.
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Pure Silica zeolite mel low k films from nanoparticle suspensions
Journal of Physical Chemistry B, 2005Co-Authors: Christopher M Lew, Dora I Medina, Yushan YanAbstract:Following our previous works on Pure-Silica-zeolite (PSZ) MFI, in this study we explore PSZ MEL as a new option for low-k dielectric films. Our motivation has been to increase the microporosity of the spin-on films by moving to structures with a framework density (FD) lower than MFI. Nanoparticle PSZ MEL suspensions were synthesized by a two-stage method that allowed the yield of nanocrystals to be significantly enhanced, while the zeolite nanocrystals remain small. For the first time zeolite nanocrystals of about 50 nm were synthesized with a yield as high as 57%. Nanoparticle suspensions with different particle sizes and crystallinities were spun on silicon wafers to prepare continuous thin films. An ultralow-k value as low as 1.5 was obtained with MEL nanoparticle suspension of high relative crystallinity. The surface roughness of the PSZ MEL film with high relative crystallinity is greatly improved (Rrms ∼ 5.6 nm) compared to MFI films with high relative crystallinity (Rrms ∼ 12 nm).
Mark E Davis - One of the best experts on this subject based on the ideXlab platform.
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further investigations of racemic and chiral molecular sieves of the stw topology
Chemistry of Materials, 2021Co-Authors: Christian Baerlocher, Michael W Deem, Jong Hun Kang, Lynne B Mccusker, Mark E DavisAbstract:Large single crystals of Pure-Silica STW-type molecular sieves are prepared using 1,2,3,4,5-pentamethylimidazolium (12345PMI) and 2-ethyl-1,3,4-trimethylimidazolium (2E134TMI) as organic structure-...
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facile synthesis and catalysis of Pure Silica and heteroatom lta
Chemistry of Materials, 2015Co-Authors: Ben W Boal, Joel E Schmidt, Mark A Deimund, Michael W Deem, Lawrence M Henling, Stephen K Brand, Stacey I Zones, Mark E DavisAbstract:Zeolite A (LTA) has many large-scale uses in separations and ion exchange applications. Because of the high aluminum content and lack of high-temperature stability, applications in catalysis, while highly desired, have been extremely limited. Herein, we report a robust method to prepare Pure-Silica, aluminoSilicate (product Si/Al = 12–42), and titanoSilicate LTA in fluoride media using a simple, imidazolium-based organic structure-directing agent. The aluminoSilicate material is an active catalyst for the methanol-to-olefins reaction with higher product selectivities to butenes as well as C5 and C6 products than the commercialized silicoalumniophosphate or zeolite analogue that both have the chabazite framework (SAPO-34 and SSZ-13, respectively). The crystal structures of the as-made and calcined Pure-Silica materials were solved using single-crystal X-ray diffraction, providing information about the occluded organics and fluoride as well as structural information.
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Pure Silica zeolite thin films by vapor phase transport of fluoride for low k applications
Microporous and Mesoporous Materials, 2010Co-Authors: Heather K Hunt, Yushan Yan, Christopher M Lew, Minwei Sun, Mark E DavisAbstract:A new method to synthesize Pure-Silica zeolite films is presented. Specifically, this method uses fluoridemediated syntheses that involve the vapor phase transport of the mineralizing agent, fluoride, to crystallize a precursor film deposited by dip-coating techniques to obtain thin films of Pure-Silica zeolites with LTA, CHA, and ITW topologies. The films are characterized by a combination of X-ray diffraction, field emission scanning electron microscopy, and X-ray energy dispersive analyses. The films are polycrystalline, intergrown, continuous and well-adhered to their substrates. The usefulness of these thin films as low-k materials, that are needed to reduce cross-talk noise and energy dissipation between transistors in an integrated circuit, is demonstrated via evaluation of the Pure-Silica LTA film. The LTA topology has the lowest framework density (FD = 14.2) of the 19 known Pure-Silica zeolites, and theoretically could have the lowest dielectric constant. The average dielectric constants of the LTA films are calculated from capacitance measurements at a frequency of 1 MHz with metal–insulator–metal structures on lowresistivity silicon substrates, and yield an average k = 1.69, well within the ultra low-k material requirements (k between 2.3 and 2.6).
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Pure Silica zeolite mfi and mel low dielectric constant films with fluoro organic functionalization
Advanced Functional Materials, 2008Co-Authors: Christopher M Lew, Mark E Davis, Dora I Medina, Minwei Sun, Yan Liu, Junlan Wang, Sonjong Hwang, Yushan YanAbstract:The synthesis of organic-functionalized Pure-Silica-zeolites (PSZs) with MFI- and MEL-type structures for low-k applications prepared through a direct-synthesis method by adding a fluorinated silane to the synthesis solution is reported. The added fluorine functionality increases the hydrophobicity of the zeolites, which are characterized by scanning electron microscopy, X-ray diffraction, 29Si and 19F solid-state NMR spectroscopy, nitrogen adsorption, and thermogravimetric analysis. The functionalized zeolite powders have low water content and calcined spin-on films prepared from the functionalized nanoparticle suspensions exhibit higher water contact angles and lower k values (2.1 and 1.8 for the functionalized MFI- and MEL-type zeolites, respectively) than PSZ films. The use of a direct-synthesis method to decrease the moisture adsorption in the films eliminates the extra post-spin-on silylation steps that are traditionally used to render the zeolite films hydrophobic.
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thermochemistry of Pure Silica zeolites
Journal of Physical Chemistry B, 2000Co-Authors: Patrick M Piccione, Miguel A Camblor, Christel Laberty, Sanyuan Yang, And Alexandra Navrotsky, Mark E DavisAbstract:A series of Pure-Silica molecular sieves (structural codes AST, BEA, CFI, CHA, IFR, ISV, ITE, MEL, MFI, MWW, and STT) is investigated by high-temperature drop solution calorimetry using lead borate solvent at 974 K. The enthalpies of transition from quartz at 298 K (in kJ/mol) are AST, 10.9 ± 1.2; BEA, 9.3 ± 0.8; CFI, 8.8 ± 0.8; CHA, 11.4 ± 1.5; IFR, 10.0 ± 1.2; ISV, 14.4 ± 1.1; ITE, 10.1 ± 1.2; MEL, 8.2 ± 1.3; MFI, 6.8 ± 0.8; MWW, 10.4 ± 1.5; and STT, 9.2 ± 1.2. The range of energies observed is quite narrow at only 6.8−14.4 kJ/mol above that of quartz, and these data are consistent with and extend the earlier findings of Petrovic et al. The enthalpy variations are correlated with the following structural parameters: framework density, nonbonded distance between Si atoms, and framework loop configurations. A strong linear correlation between enthalpy and framework density is observed, implying that it is the overall packing quality that determines the relative enthalpies of zeolite frameworks. The presence of internal silanol groups is shown to result in a slight (≤2.4 kJ/mol) destabilization of the calcined molecular sieves by comparing calorimetric data for MFI and BEA samples synthesized in hydroxide (containing internal silanol groups) and fluoride (low internal silanol group density) media.
Joël Patarin - One of the best experts on this subject based on the ideXlab platform.
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investigation of the energetic performance of Pure Silica bec type zeolite under high pressure water and 20 m licl intrusion extrusion experiments
Microporous and Mesoporous Materials, 2017Co-Authors: Laura Ronchi, Andrey Ryzhikov, Habiba Nouali, Jean T Daou, Sebastien Albrecht, Joël PatarinAbstract:Abstract The energetic performances of the Pure Silica BEC-type zeolite are determined by high pressure intrusion-extrusion experiments with water and 20 M LiCl electrolyte aqueous solution. BEC-type zeosil displays a bumper behavior with water and a shock absorber with 20 M LiCl aqueous solution. The characterization of the sample before and after intrusion-extrusion experiments shows clearly that the BEC structure is more affected in the presence of water than with the 20 M LiCl solution.
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considerations on the symmetry of Pure Silica itq 7 zeolite isv derived from 29si mas nmr and rietveld analysis
Microporous and Mesoporous Materials, 2016Co-Authors: Jeanlouis Paillaud, Lydie Tzanis, Joël Patarin, Severinne Rigolet, Bernd Marler, Hermann GiesAbstract:Abstract Pure Silica ITQ-7 zeolite of topology ISV synthesized in fluoride media possesses a 3D 12-membered-rings pore system. Originally the structure of ITQ-7 zeolite was solved and refined from a calcined sample in the highest possible space group symmetry P4 2 / mmc . This space group leads to only 5 independent silicon T sites for this structure. However, this high symmetry was not supported by solid state 29 Si MAS NMR spectroscopy. In this short communication, we show from a revised 29 Si solid state MAS NMR and Rietveld analyses, that lowering of the space group symmetry from P4 2 / mmc to P4 2 consolidates structure model and experimental data, in particular, the number of non equivalent crystallographic T sites passing from 5 to 16, is in agreement with 29 Si solid state NMR spectroscopy.
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energetic behavior of the Pure Silica itq 12 itw zeolite under high pressure water intrusion
Physical Chemistry Chemical Physics, 2013Co-Authors: Ismail Khay, Lydie Tzanis, Andrey Ryzhikov, Habiba Nouali, Jean T Daou, Joël PatarinAbstract:Experimental water intrusion–extrusion isotherms were obtained at room temperature on Pure Silica ITW-type zeolites (ITQ-12 zeosil). The water intrusion is obtained by applying a high hydraulic pressure corresponding to the intrusion step. When the pressure is released, the water extrusion occurs at a similar pressure to that of the intrusion one. Therefore, the “ITW zeosil–water” system behaves like a spring and the phenomenon is reproducible over several cycles. Several characterization techniques have been performed before and after water intrusion–extrusion experiments in order to reveal the presence or the lack of defects after such experiments. Structural modifications at the long range order cannot be observed by XRD analysis after three water intrusion–extrusion cycles. However, solid state NMR spectroscopy provides evidence of the presence of Q3 groups revealing the breaking of some siloxane bridges after the intrusion step. The “ITW zeosil–water” system can restore 100% of the stored energy corresponding to about 8 J g−1.
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High pressure water intrusion investigation of Pure Silica 1D channel AFI, MTW and TON-type zeolites
Microporous and Mesoporous Materials, 2011Co-Authors: Lydie Tzanis, Michel Soulard, Mickaël Trzpit, Joël PatarinAbstract:Abstract Experimental water intrusion–extrusion isotherms were performed at room temperature on various 1D channel Pure Silica AFI, MTW and TON-type zeolites. The water intrusion is obtained by applying a high hydraulic pressure corresponding to the intrusion step. Whatever, the zeosil, when the pressure is released, the water extrusion occurs at a similar pressure to that of the intrusion one. These “zeosil–water” systems behave like a spring and the phenomenon is reproducible over several cycles. Several characterizations have been realized before and after water intrusion–extrusion experiments in order to reveal the presence or the absence of defects after such experiments. For all samples, no structural modifications at the long range order are observed by XRD analysis. However for the MTW-type zeosil, solid state NMR spectroscopy get evidence of the presence of Q2 and Q3 groups revealing the breaking of some siloxane bridges. Nevertheless, the amount of defects is very low (
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investigation of the energetic performance of Pure Silica itq 4 ifr zeolite under high pressure water intrusion
Journal of Physical Chemistry C, 2010Co-Authors: Mohamed Ali Saada, Michel Soulard, Severinne Rigolet, Jeanlouis Paillaud, Nicolas Bats, Joël PatarinAbstract:To study the energetic performance of the 1D 12-membred-ring Pure Silica ITQ-4 zeolite (IFR topology), a high-pressure water intrusion−extrusion isotherm at room temperature was performed. The pressure−volume diagram indicates an irreversible phenomenon, water molecules remaining confined in ITQ-4 micropores. Therefore, the “water−ITQ-4” system appears to behave as a bumper. The water intrusion pressure and intruded volume are of 42 MPa and 0.136 mL/g, respectively. Investigations on the ITQ-4 samples by 29Si and 1H solid-state NMR spectroscopy and powder X-ray diffraction have confirmed the existence of a small amount of silanol defects in the nonintruded sample and an increase of these defects after the water intrusion−extrusion experiment. It appears clearly that one of the crystallographic silicon sites of the porous framework is particularly affected after such a treatment, leading to the creation of Si−OH groups by the breaking of siloxane bonds, these silanols being strongly hydrogen bonded with wa...
Avelino Corma - One of the best experts on this subject based on the ideXlab platform.
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insights into adsorption of linear monobranched and dibranched alkanes on Pure Silica stw zeolite as a promising material for their separation
Journal of Physical Chemistry C, 2020Co-Authors: Eduardo Perezbotella, Avelino Corma, Alechania Misturini, Andres Sala, Miguel Palomino, German Sastre, Susana Valencia, Fernando ReyAbstract:The adsorption of linear, monobranched and dibranched saturated hydrocarbons in the gasoline range has been studied on Pure Silica STW zeolite (Si-STW) by using pentane, hexane, and heptane isomers...
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preparation of continuous highly hydrophobic Pure Silica itq 29 zeolite layers on alumina supports
Molecules, 2020Co-Authors: Miguel Palomino, Susana Valencia, Hideki Ono, Avelino CormaAbstract:The preparation of continuous layers of highly hydrophobic Pure Silica ITQ-29 zeolite, potentially applicable as hydrophobic membranes for separation of molecules based on their polarity, has been investigated. Continuous layers of intergrown ITQ-29 zeolite crystals were successfully grown on porous alumina supports by optimization of the synthesis conditions, such as the appropriate selection of the seeds, the procedure for the gel preparation, and the calcination conditions. This resulted in the formation of all Silica ITQ-29 zeolite layers without the presence of germanium required in previously reported ITQ-29 membranes, with the subsequent improvement in quality and stability, as verified by the absence of cracks after calcination. We have proved that the incorporation of aluminum from the support into the zeolite layer does not occur, neither during the secondary growth nor through migration of aluminum species during calcination.
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synthesis of expanded titanoSilicate mww related materials from a Pure Silica precursor
Chemistry of Materials, 2012Co-Authors: Manuel Moliner, Avelino CormaAbstract:TitanoSilicate forms of expanded MWW-related material are synthesized starting from a Pure Silica precursor, ITQ-1. This procedure improves the current synthetic route of the expanded titanoSilicate MWW material (Ti-YNU-1), which requires the use of a boroSilicate MWW as precursor and, consequently, several postsynthetic acid treatments for removing boron atoms from the framework. The expanded Ti-MWW-related materials presented here show better activity than regular Ti-MWW in the selective epoxidation reaction of cyclohexene using H2O2 as oxidant.
Masaaki Hirano - One of the best experts on this subject based on the ideXlab platform.
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low loss and low nonlinearity Pure Silica core fiber for c and l band broadband transmission
Journal of Lightwave Technology, 2016Co-Authors: Yoshinori Yamamoto, Yuki Kawaguchi, Masaaki HiranoAbstract:In order to improve system optical signal-to-noise ratio, low-loss and low-nonlinearity fibers are demanded for ultra-long-haul and high-capacity digital coherent transmission systems, such as transoceanic systems. In order to meet the demand, we have realized a Pure-Silica-core fiber with ultra-low loss of 0.15 dB/km and large effective area (Aeff) of 130 μm2 (PSCF-130). Recently, transmission systems utilizing the L-band in addition to the C-band have been actively studied to further expand transmission capacity through a fiber. In such systems, however, one concern is loss increase resulting from macro- and/or micro-bending losses of large Aeff fiber. In this paper, we show experimentally and theoretically that PSCF-130 has sufficiently low macro- and micro-bending losses even in the L-band. PSCF-130 also has high-fiber figure-of-merit because of ultra-low loss and large Aeff in the C- and L-bands. From these results, PSCF-130 is applicable for C- and L-band broadband transmission and will have high transmission performance.
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a comparison between ssmf and large a eff Pure Silica core fiber for ultra long haul 100g transmission
Optics Express, 2011Co-Authors: V A J M Sleiffer, Masaaki Hirano, Z Maalej, D Van Den Borne, M Kuschnerov, V Veljanovski, Yoshinori Yamamoto, Takashi Sasaki, S L Jansen, Antonio NapoliAbstract:We compare the transmission performance of 112-Gb/s POLMUX-QPSK modulation over large-Aeff Pure-Silica core fiber and SSMF using EDFA-only amplification. The higher nonlinear threshold of the large-Aeff Pure-Silica core fiber allows for a 55% increase in transmission distance. By using back-propagation an additional 10% increase is observed. In case spans with equal length for both fiber types and two splices per span only would have been used, resulting in a lower span loss for the large-Aeff Pure-Silica core fiber, the total increase grows to 85%.
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osnr enhancing Pure Silica core fiber with large effective area and low attenuation
Optical Fiber Communication Conference, 2010Co-Authors: Yoshinori Yamamoto, Masaaki Hirano, Kazuya Kuwahara, Takashi SasakiAbstract:Pure-Silica-core fiber with large Aeff of 134μm2 is designed to enhance OSNR considering splice loss to SSMF, and realized by appropriate depressed cladding profile and soft primary coating. It also exhibits low attenuation of 0.169dB/km.
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low loss dispersion flattened hybrid transmission lines consisting of low nonlinearity Pure Silica core fibres and dispersion compensating fibres
Electronics Letters, 2000Co-Authors: Masao Tsukitani, Masaaki Hirano, T Kato, Eiji Yanada, M Nakamura, Yuichi Ohga, M Onishi, Eisuke Sasaoka, Y Makio, M NishimuraAbstract:Newly developed design-optimised hybrid transmission lines are presented which consist of Pure Silica core fibre and dispersion compensating fibre, and exhibit a span loss of 0.205 dB/km, a span dispersion slope of 0.020 ps/nm2/km and low nonlinearity with an equivalent effective area of 60 µm2.
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ultra low nonlinearity low loss Pure Silica core fibre for long haul wdm transmission
Electronics Letters, 1999Co-Authors: Takatoshi Kato, Masaaki Hirano, Masashi Onishi, Masayuki NishimuraAbstract:A new design of Pure Silica core fibre with an effective area >110 /spl mu/m/sup 2/ and attenuation of 0.171 dB/km at 1.55 /spl mu/m has been successfully developed. It exhibits ultra-low nonlinearity and excellent bending loss performance.
