Experimental study of single-mode W-type optical fibre

The development and experimental study of a single-mode W-type optical fibre is described. It was found that this type of optical fibre has considerably lower bending and micro-bending losses compared with usual single-mode single-cladding fibres.     

High-purity chalcogenide glasses for fiber optics

The data on the present degree of purity of chalcogenide glasses for fiber optics, on their methods of production and on the properties, which are essential for their actual application, are generalized. The content of limiting impurities in the best samples of chalcogenide glasses is 10–100 ppb wt.; of heterophase inclusions with size of about 100 nm is less than 10³ cm^?3. On the basis of chalcogenide glasses the multimode and single mode optical fibers are produced with technical and operation characteristics sufficient for a number of actual applications. The minimum optical losses of 12–14 dB/km at 3–5 µm are attained in the optical fiber from arsenic-sulfide glass. The level of losses in standard chalcogenide optical fibers is 50–300 dB/km in 2–9 µm spectral range. The factors, affecting the optical absorption of glasses and optical fibers, are analyzed, and the main directions in further development of chalcogenide glasses as the materials for fiber optics are considered.     

Refractive index spectral dependence, Raman spectra, and transmission spectra of high-purity 28Si, 29Si, 30Si, and natSi single crystals

We performed precise measurement of the refractive index of stable silicon isotopes 28Si, 29Si, and 30Si single crystals with enrichments above 99.9?at.% and a silicon single-crystal natSi of natural isotopic composition with the Fourier-transform interference refractometry method from 1.06 to more than 80?μm with 0.1?cm(-1) resolution and accuracy of 2×10(-5)…1×10(-4). The oxygen and carbon concentrations in all crystals are within 5×10(15)?cm(-3), and the content of the metal impurities is 10(-5)…10(-6)?at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of the generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.     

Dynamics of the drawing zone of a lightguide blank for different drawing regimes with furnace and laser heating

The results of numerical modeling of the process of drawing a quartz blank into a lightguide with different mehtods of heating are presented. The optimal regions of the space of drawing parameters for obtaining a stable lightguide diameter are determined.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 3, pp. 491–497, September, 1988.     

Catastrophic destruction of fluoride and chalcogenide opticalfibres

Catastrophic destruction of fluoride and chalcogenide optical fibres under laser radiation in the wavelength region 1-1.5 μm has been investigated for the first time. Different characteristics and much lower thresholds of catastrophic damage compared to silica-based fibres have been discovered     

Monolithic capillary columns for analysis of permanent gases and light hydrocarbons

Monolithic capillary columns based on divinylbenzene and ethylene glycol bis(acrylate) polymers were applied toward the analysis of permanent gases and light C₁-C₂ hydrocarbons by gas chromatography. It was shown that columns on the basis of the ethylene glycol bis(acrylate) polymer demonstrate better separating ability and make it possible to separate all components of the standard mixture at room temperature except the N₂/O₂ pair. The columns on the basis of divinylbenzene exhibit lower selectivity but make it possible to perform rapid analysis of the standard mixture with an analysis time less than 2 min.     

Production and properties of high purity TeO2–ZnO–Na2O–Bi2O3 and TeO2–WO3–La2O3–MoO3 glasses

High-purity TeO₂–ZnO–Na₂O–Bi₂O₃ and TeO₂–WO₃–La₂O₃–MoO₃ glasses were produced by melting the high-purity oxides mixtures in platinum or gold crucible at 800 °C in hermetic chamber in the purified oxygen atmosphere. The content of limiting impurities in the produced initial oxides and glasses, the optical properties as well as the stability to crystallization were investigated. The optical fibers were produced from high-purity tellurite glasses with losses at the level of several hundreds of dB/km.The total content of 3d-transition metals in the glasses was not more than 1 ppm wt and content of hydroxyl groups corresponded to the absorption level of 0.001–0.002 cm⁻¹ at ∼3 μm. The absorption band, monotonically increasing with the increase in MoO₃ content, was observed in dry TeO₂–WO₃–La₂O₃–MoO₃ glasses with the maximum at about 3.7 μm.