V. V. Kashin

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.

Physical properties and crystal microstructure of the single crystal fibres made from rare-earth oxides

Single crystal fibres on a basis rare-earth oxides are promising materials for technical application, in particular for radiation delivery in a near and mid-IR range. In the fibres shape Eu3+:Y2O3 [1], Ln3+:Gd2O3 (Ln=Nd, Eu, Er) [2,3] single crystals have been received earlier and their luminescent properties have been studied. The goal of our study consisted in the interrelation analysis between a microstructure of fibres and their such property as the plasticity expressed in their ability to be easily bent. Another goal was the study of nonlinear properties consisted in the possibility to produce super continuum generation during the transmission of the ultrashort light pulses. Fibres Ln2O3 (Ln=Sm, Eu, Gd) have been grown up by a method of “a laser minipedestal” on ZrO2 crystal seed. Among the grown up fibres there were both fragile, and flexible plastic. According to X-ray crystal phase analysis in all of them Ln2O3 are crystallized in monoclinic system and do not contain additional cubic crystal phase stable at low temperatures (a limit of detection of about 1 %). A series X-ray diffraction patterns obtained with initial, bent and straightened fibres shows, that at deformation the reflexes on Laue pattern are diffused, but there is practically full restoration of clearness of reflexes at restoration of the initial shape of a fibre. The morphology of the samples surface was studied, the chemical composition is determined by the X-ray microanalysis, orientation of crystals is established by a method of diffraction of back scattered electrons (EBSD). On the fibres surface the rings are observed and they are allocated with distances between them of about 0,3–2 µm (Fig. 1)

Microstructure and properties of single-crystal rare-earth oxide fibers

Single-crystal Ln2O3 (Ln = Sm, Eu, Gd) fibers are grown by the laser-heated miniature pedestal technique. The relationship between the microstructure of fibers and their plasticity is analyzed using scanning electron microscopy, energy-dispersive microanalysis, electron backscatter diffraction, and X-ray methods. It is shown that the distinction between ductile and brittle fibers is determined basically by the difference in their microstructure. The fracture of samarium oxide fibers is associated with the formation of oxycarbonate phases on their surface. The most promising are the fibers of gadolinium oxide, having the most perfect microstructure, moisture and a carbon dioxide resistance, and a wide range of transparency.

Magnetic Applicator for Depositing Polymer Coatings on Quartz Light Guides

The operating principle and characteristics of applicators based on disperse magnetic systems intended for deposition of protective polymer coatings on quartz light guides are described. The possibility of controlling the parameters of coatings in drawing light guides is demonstrated.

Lightguide fabrication control with a laser heater

The problem of controlling the diameter of a fabricated fiber with the help of an auxiliary low-power laser heater is analyzed.