Optické vláknové senzory fyzikálních veličin.

Abstract

This thesis deals with uzilization of highly birefringent optical fibers in fiber optic sensors, mainly in temperature sensing. For this purpose white-light spectral interferometry is exploited. The thesis introduces principles of guiding of electromagnetic field in optical fibers, describes special optical fibers and analyzes spectral interference of waves at the output of an experimental setup. Furthermore, results of measurements of spectral interference with utilization of diverse experimental setups and birefringent fibers types are presented and discussed. In experiments, interference of optical waves is exploited, whereas these are orthogonally polarised modes of birefringent optical fibers or ordinary and extraordinary wave of a birefringent crystal. It is advantageous that these waves are in visible or near infrared part of spectrum which lowers demands on used light source and detector. Described experiments show how optical fibers can be used in sensors for sensing diverse physical quantities and demonstrate a possibility of utilization of the Vernier effect for given measurement sensitivity enhancement. Beside optical fiber temperature sensors the thesis in experimental part also deals with an optical displacement sensor utilizing a Michelson interferometer in a standard configuration and in a configuration utilizing the Vernier effect to measurement sensitivity enhancement.