Preparation of Infrared Optic Fibers Using New Materials

摘要

This report summarizes an eighteen-month program on the preparation and characterization of optical fibers which have low losses and are transparent in the infrared range. The objectives were to study preparative techniques, compositional and optical properties, and factors which influence fiber growth techniques. The emphasis of this program was on single crystal fibers in the size range from 100 - 1000 micrometer diameter. Single crystal fibers were produced in limited lengths using two techniques: the laser heated pedestal growth technique for high-melting materials, and the capillary-fed fiber growth method for low-melting and for volatile materials. The materials studied were selected from those which have a high potential for low loss at wavelengths greater than 1.5 micrometers, and included BaF2, CaF2, AgBr, and KRS-5. The fibers were analyzed using metallographic, optical, XRD, and energy dispersive analytical techniques. Critical system and growth parameters were studied, and factors which correlated with the occurrence of internal structural and optical defects were identified. This study demonstrated the feasibility of growing a range of IR fibers with both the laser-heated pedestal and the capillary-fed growth techniques.