Surface Relief D-Fiber Bragg Gratings for Sensing Applications Surface Relief D-Fiber Bragg Gratings for Sensing Applications
For traditional fiber Bragg gratings the index modulation occurs in the core of the optical fiber. While this method can produce highly reflective gratings they are not well suited for many sensing applications. For example, the operating temperature range is limited to a few hundred degrees Celsius before the index modulation returns to a more uniform index profile. Also because the gratings are created in the core of the fiber, interaction with the surrounding environment is limited.
The surface relief fiber Bragg grating created for this work overcomes some of the sensing challenges of traditional gratings. The major accomplishments of this dissertation show a dramatic increase in operating temperature to over 1000 degrees Celsius, the ability to measure multi-dimensional bend, the ability to measure material changes around the fiber such as chemical concentration, and the ability to use a Vernier effect to dramatically increase the sensors sensitivity.
In addition to the sensing applications of this work a more thorough understanding of the reflection and transmission properties of the surface relief grating is also presented. Implementation of the transfer matrix method for simulation of the gratings is also shown to be a fast and accurate modeling tool for predicting the grating response.
School:Brigham Young University
School Location:USA - Utah
Source Type:Master's Thesis
Keywords:fiber bragg gratings high temperature sensing chemical bend vernier d optical surface relief structured
Date of Publication:10/24/2008