Sol-Gel Processing of Optical Fiber

1986 ◽  
Vol 88 ◽  
Author(s):  
M. E. Elias ◽  
A. M. Elias
Keyword(s):  
Optical Fiber ◽  
Transmission Loss ◽  
Amorphous Material ◽  
Sol Gel ◽  
Sintering Process ◽  
Exponential Time ◽  
Fiber Production ◽  
Hydrolytic Polycondensation ◽  
Gel Processing ◽  
Solid Glass

ABSTRACTA new method for optical fiber production is shown. Hydrolytic polycondensation of tetramethoxysilane using a low concentration of α-picoline, 1.56×10−3% in water, gives SiO2 gel which was dried at 22 °C to a transparent amorphous material.The densification process shows an exponential time dependence with a final value of 2.253 g/cm3 after 30 days. The specific surface area of the porous gel varies from 500 to 600 m2/g but pores are eliminated by the sintering process. Before sintering the gel, it is treated under an oxidizing atmosphere above 700 °C. At 1200 °C the pores are eliminated and a solid glass rod obtained.After the sintering process a fiber is obtained from the rod which shows a transmission loss as low as 5.5 dB/km at 840nm.

scholarly journals Preparation and morphology of porous SiO2 ceramics derived from fir flour templates

2010 ◽  
Vol 75 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Li Zhong ◽  
Tiejun Shi ◽  
Liying Guo
Keyword(s):  
Amorphous Material ◽  
Sol Gel ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Ordered Structures ◽  
Porous Sio2 ◽  
Pore Size Distributions ◽  
Naoh Solution ◽  
Gel Processing ◽  
Highly Porous

The preparation of SiO2 ceramics with controllable porous structure from fir flour templates via sol-gel processing was investigated. The specific size the fir flour, which was treated with 20 % NaOH solution, was infiltrated with a low viscous silica sol and subsequently calcined in air, which resulted in the formation of highly porous SiO2 ceramics. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were employed to investigate the microstructure and phase formation during processing as well as of the SiO2 ceramics. N2 adsorption measurements were used to analyze the pore size distributions (PSD) of the final ceramics. The results indicated that the surface topography was changed and the proportion of the amorphous material was increased in NaOH-treated fir flour. The final oxide products retained ordered structures of the pores and showed unique pore sizes and distributions with hierarchy on the nanoscale derived from the fir flour.

Dense and optical transparent CdWO4 films by sol-gel processing for scintillation applications

2007 ◽  
Vol 22 (6) ◽  
pp. 1527-1536 ◽  
Author(s):  
H.M. Shang ◽  
M. Bliss ◽  
S. Heald ◽  
T.K. Sham ◽  
F. Heigl ◽  
...  
Keyword(s):  
Sol Gel ◽  
Tungstic Acid ◽  
Cadmium Nitrate ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Luminescence ◽  
Optically Transparent ◽  
Rapid Sintering ◽  
Gel Processing

In this paper, we report the first successful fabrication of dense and optically transparent cadmium tungstate (CWO) films by sol-gel processing and the study of their optical and x-ray scintillation properties. A new sol-gel processing method was developed using tungstic acid and cadmium nitrate as precursors and hydrogen peroxide as solvent; homogeneous and stable CWO sols were aged at room temperature and used for the preparation of CWO films. A rapid sintering process was investigated and found to be necessary to make dense and optically transparent nanocrystalline CWO films. CWO films were uniform, fully dense, and crack-free, with CWO as the only detectable crystalline phase, as determined by x-ray diffraction. The thickness, density, grain size, and crystallinity of CWO films are all found to be strongly dependent on the sintering conditions and in turn impact the optical and x-ray scintillation properties. Sol-gel-derived dense CWO films demonstrated intense photoluminescence and x-ray excited optical luminescence intensity. The relationships between sol-gel processing, nanostructures, and optical and x-ray scintillation properties are discussed in detail.

Densification and Evolution of Stress Development in Solution Derived PbZr0.53Ti0.47O3 Thin Layers

1999 ◽  
Vol 596 ◽  
Author(s):  
Sang M. Park
Keyword(s):  
Sol Gel ◽  
Film Plane ◽  
Thin Layers ◽  
Silicon Substrates ◽  
Sintering Process ◽  
Stress Development ◽  
Insertion Method ◽  
Gel Processing ◽  
Reflectance Measurements

AbstractStress development in thin layers of PbZr0.53Ti0.47O3 (PZT) and PbTiO3 (PT) prepared by sol-gel processing was monitored by in situ laser reflectance measurements. Layers were spin coated onto silicon substrates and thermally cycled to 600°C and 650°C. The shrinkage normal to the film plane was determined by in situ ellipsometry and scanning electron microscopy. Both PZT and PT multilayers showed a similar stress behavior on heating, but quite different behavior on cooling. As the film became dense at high temperatures, total stress was dominated by the thermal expansion mismatch between the oxide layer and the substrate. On cooling, the PT multilayers, which already crystallized into the perovskite structure, ended nearly stress free at room temperature, whereas mostly amorphous PZT multilayers were under a high tensile stress. Densification in PZT layers appeared to occur between 370°C and 520°C. At near 370°C the shrinkage mode for a single PZT layer was also observed to change substantially. A two-stage sintering process employing 450°C-sintering and 650°C-crystallization was found to be as effective as direct furnace insertion method in producing a dense film.

Synthesis and characterization of BaMgAl10O17:Eu phosphors derived by sol–gel processing

2002 ◽  
Vol 126 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Junying Zhang ◽  
Zhongtai Zhang ◽  
Zilong Tang ◽  
Zishan Zheng ◽  
Yuanhua Lin
Keyword(s):  
Sol Gel ◽  
Synthesis And Characterization ◽  
Gel Processing

Chemical Solution Deposition of Lanthanum Zirconate Buffer Layers on Biaxially Textured Ni–1.7% Fe–3% W Alloy Substrates for Coated-conductor Fabrication

2002 ◽  
Vol 17 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
T. Aytug ◽  
B. W. Kang ◽  
P. M. Martin ◽  
...  
Keyword(s):  
Sol Gel ◽  
Rf Sputtering ◽  
Cube Texture ◽  
Dip Coating ◽  
Buffer Layers ◽  
Lanthanum Zirconate ◽  
Solution Deposition ◽  
Ybco Films ◽  
Current Densities ◽  
Gel Processing

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.

Microstructure and Microwave Dielectric Properties of BaTi4O9 Ceramics Derived from a Sol-Gel Precursor

2011 ◽  
Vol 326 ◽  
pp. 127-130
Author(s):  
Xian Li Huang ◽  
Fu Ping Wang ◽  
Ying Song
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Quality Factor Q

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

Effect of acetylacetone on the preparation of PZT materials in sol–gel processing

2002 ◽  
Vol 96 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Luqian Weng ◽  
Xujin Bao ◽  
Kwesi Sagoe-Crentsil
Keyword(s):  
Sol Gel ◽  
Gel Processing

Diamond Machinable Sol-Gel Silica Based Hybrid Coatings for High Precision Optical Molds

2010 ◽  
Vol 438 ◽  
pp. 65-72 ◽  
Author(s):  
Andreas Mehner ◽  
Ju An Dong ◽  
Timo Hoja ◽  
Torsten Prenzel ◽  
Yildirim Mutlugünes ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Precision ◽  
Sol Gel ◽  
Processing Parameters ◽  
Hybrid Coatings ◽  
Optical Elements ◽  
Optical Components ◽  
New Approach ◽  
Free Silica ◽  
Gel Processing

The demand for high precision optical elements as micro lens arrays for displays increases continually. Economic mass production of such optical elements is done by replication with high precision optical molds. A new approach for manufacturing such molds was realized by diamond machinable and wear resistant sol-gel coatings. Crack free silica based hybrid coatings from base catalyzed sols from tetraethylorthosilicate (TEOS: Si(OC2H5)4) and methyltriethoxysilane (MTES: Si(CH3)(OC2H5)3) precursors were deposited onto pre-machined steel molds by spin coating process followed by a heat treatment at temperatures up to 800°C. Crack-free multilayer coatings with a total thickness of up to 18 µm were achieved. Micro-machining of these coatings was accomplished by high precision fly cutting with diamond tools. Molds with micro-structured coatings were successfully tested for injection molding of PMMA optical components. The wear resistance of the coatings was successfully tested by injection molding of 1000 PMMA lenses. Hardness and elastic modulus of the coatings were measured by nano indentation. The chemical composition was measured by X-ray photo electron spectroscopy (XPS) as a function of the sol-gel processing parameters.

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