Sapphire-optical-fiber-based interferometric sensors for high-temperature environmental applications

摘要

Abstract: We describe the development and testing of intrinsicand extrinsic sapphire fiber-based sensor designsintended for use in high temperature environments. Thefirst is a sapphire-fiber-based intrinsicinterferometric sensor. In this sensor, a length ofuncoated, unclad, structural-grade multimode sapphirefiber is fusion spliced to a singlemode silica fiber toform a Fabry-Perot cavity. The reflections from thesilica-to-sapphire fiber splice and the free endface ofthe sapphire fiber give rise to the interfering fringeoutput. This sensor has been demonstrated for themeasurement of temperature above 1510$DGR@C, and aresolution of 0.1$DGR@C has been obtained. The secondis an extrinsic sapphire fiber-based Fabry-Perotinterferometer. Based on the intrinsic sapphire fibersensor, another sapphire fiber is placed end-to-end tothe first sapphire fiber and the two adjacent endfacesof the two sapphire fibers form a Fabry-Perot cavity.This sensor has been shown to be useful for strain andtemperature measurement. !10