Ion-exchange Glass Optical Fiber And Its Applications In Measuring Refractive Index Of Fluids

With the development of optical communication technology and the increasing demand for high-quality optical waveguides, the new materials and new preparation methods are investigated to fabricate high quality optical waveguide. Glass fiber material based on copper ion exchange with a large third-order nonlinear coefficient, blue-green luminescence characteristics and broadband fluorescence spectroscopy have bright prospects for research value. High-precision measurement techniques are also attracting increasing attention. In this paper, attentions are mainly focused on both fabrication and characterization of glass fiber based on ion exchange and application of measuring the refractive index of liquid based on retroreflection of optical fiber. The main progresses are listed below:1. In the part of fabrication, the glass optical fiber waveguide based on copper ion exchange were first proposed. At first, we introduced the physical mechanism of ion exchange. Second, we choosed Soda-lime glass as the base of ion exchange and CuSO4 and Na2SO4 as the mixed solution. Then the experimental samples are done to EDX and SEM tests to confirm the content distribution of copper after ion exchange. Transmission loss experiments shows that the lowest propagation loss of sample was 1.120dB/cm. Meanwhile, the experiments of fluorescence spectrum shows that the samples have a very wide range of light from 375nm to 475nm. These characterizes of glass optical waveguide has great potential value in manufacturing of broadband fluorescent light source and visible tunable pulsed laser.2. Theoretical simulations of WGM mode of glass optical waveguide after ion exchange have been proposed. We simulated the propagation constant of the waveguide from the intrinsic equation and electric field distribution based on WGM mode. And then we proposed ring resonator sensor and blue-green band of the WGM microcavity laser based on the above simulations.3. An improved method using double light paths and optical circulator to measure the refractive index of liquids has been proposed. The improved experimental setup avoids possible laser source power shift and detector response changes. Meanwhile, the setup eliminates the dramatic changes in the external environment for the experimental measurements. Through experimental results show that the refractive index of the liquids are proportional to the concentration, and inversely proportional to the temperature. The measurement results show that the improved method is with a high-precision at the order of 10-4 and thermal optical coefficient is -2.3×10-4. So the improved experimental setup can be used as temperature sensors.