FIBER OPTIC DISPLACEMENT SENSING MONITORED BY AN OTDR AND REFERENCED BY FRESNEL REFLECTION AND BY FIBER BRAGG GRATINGS

摘要

This work presents a study of displacement sensing based on a fiber eight geometry shape monitored by an optical time domain reflectometer. The displacement sensor is referenced by Fresnel reflection or by a fiber Bragg grating structure located after the sensor. One of the advantages of the fiber Bragg grating as referencing device is its capability to be multiplexed by a number of displacement sensors in series along the optical fiber. This concept is also demonstrated using two Bragg gratings.