Research On Micro-Interferometer Device Sensors Based On Silica Optical Waveguide

In recent years, new methods applied for fabricating the next generation optical sensors have been available due to the rapid development of laser micro-machining technology. Optical sensors fabricated on optical waveguide by using laser micro-machining would be an important branch of modern sensing research. The optical properties of several interferometers designed on optical waveguide have been analyzed in electromagnetic theory. Furthermore, those properties have been computed by utilizing the finite element method and the optical transfer matrix theory before the devices are examined in experiment. The main accomplishments of the work are as follows:1. The work starts with the analysis of the transmission properties of strip waveguide and optical fiber by using electromagnetic theory. The electric field profile and reflective spectrum of the Fabry-Perot interferometer based on symmetry three layers planar waveguide are obtained with the help of the finite element method. The reflective spectrum of the fiber Bragg grating is given by simulation.2. A refractive index sensor based on Michelson interferometer is fabricated efficiently on silica optical splitter by using the one-step technology based on 157 nm mask laser micromachining. The sensing properties of the device which are examined by experiment are discussed in theory and predicted by simulation first.3. A highly integrated fiber-optic sensor with a regenerated fiber Bragg grating and a micro Fabry-Pérot is proposed and demonstrated for dual parameter measurement under high temperature. The sensing principle and the sensing properties have been developed in theory and predicted by simulation. A novel fiber gas pressure sensing structure with open Fabry-Perot cavity is proposed and implemented, which raises the sensitivity nearly two orders of magnitude compared with those traditional non-diaphragm fiber pressure sensors. All of these sensing properties mentioned above have been examined in a temperature as high as 600℃, which turns out that the sensor has such a weak cross sensitivity that the influence induced by temperature variation can be eliminated.4. This work has examined the optical properties of interferometers fabricated on waveguide both in theory and by numerical simulation. The goal of manufacturing microinterference structure on waveguide efficiently by using 157 nm laser system is preliminarily accomplished.