Manufacture Of Waveguides Research Articles

Synthesis and characterization of K2O-ZnO-GeO2-SiO2 optical glasses

Germanosilicate glasses are essential in the manufacture of optical amplifiers, waveguides, and solid-state lasers. ZnO, with a wide direct band gap of 3.37 eV, has a broad range of applications in UV-shielding materials. To the best of our knowledge, no previous research adding ZnO into germanosilicate glasses has been reported. In this study, thirteen samples centered around a molar composition of 20K2O-20ZnO-40GeO2-20SiO2 were melted, and the composition-property relationships were investigated. The densities are in the range of 3.18–3.46 g/cm3 and the refractive index values (RI) are between 1.588 and 1.630, close to the RI of pure GeO2 (1.603). Density and RI values increase with GeO2 and SiO2 concentrations. The UV cut-off edge is between 313 and 320 nm, significantly higher than the 157 nm value in typical soda lime glass. Fragility (m) and glass transition temperature (Tg) were determined by fitting viscosity data with the MYEGA equation. The Tg from the MYEGA equation is in good agreement with Tg values from DSC. Thermal expansion coefficient of samples is in the range of 102.7 to 139.2 × 10−7/°C, mainly influenced by the amount of ZnO and K2O. We conclude that these samples have relatively high refractive index, high transparency, good glass forming ability, and good UV-shielding properties, making them suitable for lens applications.

High resolution structural characterisation of laser-induced defect clusters inside diamond

Laser writing with ultrashort pulses provides a potential route for the manufacture of three-dimensional wires, waveguides, and defects within diamond. We present a transmission electron microscopy study of the intrinsic structure of the laser modifications and reveal a complex distribution of defects. Electron energy loss spectroscopy indicates that the majority of the irradiated region remains as sp3 bonded diamond. Electrically conductive paths are attributed to the formation of multiple nano-scale, sp2-bonded graphitic wires and a network of strain-relieving micro-cracks.

Focussing over the edge: adaptive subsurface laser fabrication up to the sample face

Direct laser writing is widely used for fabrication of subsurface, three dimensional structures in transparent media. However, the accessible volume is limited by distortion of the focussed beam at the sample edge. We determine the aberrated focal intensity distribution for light focused close to the edge of the substrate. Aberrations are modelled by dividing the pupil into two regions, each corresponding to light passing through the top and side facets. Aberration correction is demonstrated experimentally using a liquid crystal spatial light modulator for femtosecond microfabrication in fused silica. This technique allows controlled subsurface fabrication right up to the edge of the substrate. This can benefit a wide range of applications using direct laser writing, including the manufacture of waveguides and photonic crystals.

Deposition of SiO2Nanoparticles Produced in a Turbulent H2/Om2Flame

Measurements and simulations of an industrial outside vapor deposition process as used for the manufacture of optical wave guides were performed. Deposition efficiencies, flame temperatures, and gas velocities were measured. The hydrogen flame reaction was modeled by calculating the turbulent flow including a combustion model and using a computational fluid dynamics (CFD) solver to compute flow velocities, turbulence and temperatures in the flame. These results were compared with experimental data and reasonable agreement was found. The produced SiO 2 particles with predefined size were tracked through the flow field and it was determined whether they hit the surface of the cylindrical target or pass it. Three flame configurations were investigated and the model could predict well the trends of the deposition efficiencies for the different flames. The differences in flame velocities and turbulence levels for the different configurations assisted the explanation of the performances of the flames. Turbulenc...

Laser polishing of glass articles

A technique and equipment are proposed for polishing of glass articles with a carbon dioxide laser beam. The technique can be used as the finishing operation in the manufacture of lenses, expensive glassware, and light waveguides to enhance surface finish and to reduce surface roughness.

The influence of the pseudo-mixed-alkali effect on the field-assisted diffusion of silver ions into glass for optical waveguides

Results are presented from a study of the field-assisted diffusion of silver ions from silver films into soda-lime glass. These indicate that it is necessary to take into consideration the concentration dependence of the self-diffusion coefficient of both the silver and the sodium ions in a pseudo-mixed-alkali effect in order to predict the silver diffusion profiles accurately. A field assisted diffusion model that incorporates this effect is developed and model coefficients are deduced. The model is applied to post-bake diffusions and deep field-assisted diffusion profiles. The model is applicable to the design and manufacture of optical waveguides and lenses in glass by field-assisted diffusion.

Efficient modal dispersion phase-matched frequency doubling in poled polymer waveguides

We report the design, manufacture, and characterization of poled polymer multilayer waveguides for frequency doubling. Phase matching is obtained by using modal dispersion between the zeroth-order fundamental lightwave and the first-order second-harmonic wave. By incorporating a very thin high refractive index satellite layer, the phase-match condition can be fulfilled with concomitant large overlap between the two waves, resulting in efficient doubling.

Chemical Reactions in the Manufacture of Waveguides for Long Distance Optical Data Transmission

One of the modern high technologies which has advanced enormously in the last few years is glass fiber technology. This is used in the manufacture of glass fibers for lighting purposes and for the optical transfer of analog and digital data with a high transfer density. The technical demands made on the glass fibers required for data transfer, the optical waveguides, are extremely high and are already fulfilled to a large extent by industry. At present about four million kilometers of fiber, worth ca. 800 million DM are produced worldwide (10% in the Federal Republic of Germany). Numerous chemical processes take place during the manufacture of optical waveguides. However, in contrast both to the high and constantly growing demands on the quality and to the increasing production volume of such fibers, little is in fact known about the reactions involved. The present article will attempt to develop a picture of the multifarious reactions occurring in the course of this technical process on the basis of literature data and our own studies.

Modeling and analysis of modified chemical vapor deposition of optical fiber preforms

A theoretical analysis of modified chemical vapor deposition (MCVD) for the manufacture of optical waveguides is presented. The Navier—Stokes equations are solved, including continuity, momentum, energy and mass balance equations for gas components and SiO 2 particles accounting for heat transfer, chemical reaction, convection, gas diffusion and SiO 2 thermophoresis. The effects of process variables (gas flow rate and inlet SiCl 4 concentration) on MCVD operation are examined. The heat of reaction reduces the radial diffusion of the precursor gas and, subsequently, the MCVD deposition efficiency. Employing helium as the carrier gas results in the fastest reaction and deposition rates, but exhibits the lowest deposition efficiency of the process. High process yields are favored by high inlet SiCl 4 concentrations and fast gas flow rates through the preform tube.

MANUFACTURE OF OPTICAL WAVEGUIDES USING AEROSOLS: A REVIEW

ABSTRACT Optical waveguides are glass filaments used to transmit light for telecommunication and other uses. To achieve high performance, inexpensive optical communication systems require: glass of exceptional purity and precise control of glass refractive index. For this reason, aerosol deposition is utilized exclusively for the manufacture of optical waveguides. The applications and operation of optical waveguides are outlined in this paper. The major manufacturing processes are discussed, with emphasis on aerosol formation and deposition.