Design Of Asymmetric Planar Optical Waveguide And Its Response To Organic Gases

Nowadays,with the rapid development of the sensing technology,the unperceived parameters can be visualized and presented in data or images.In view of the multi-layer planar optical waveguide technology,an asymmetric five-layer planar optical waveguide structure is designed instead of a symmetric structure to explore its applications in the field of gas sensors,which some poisonous and harmful gases can be monitored.In this thesis,the five-layer planar optical waveguide structure is analogized to the Young's double-slit interference.The experimental evidence shows that Young's double-slit interference theory can be applied to analysis the five-layer planar optical waveguide interference fringes correctly.By using computer software,the structure is optimized from five symmetrical planar optical waveguide structure to the asymmetric structure.The low concentration organic gases of ethanol,xylene and isoamyl acetate were prepared by using a gas preparation system,and the upper cladding of the asymmetric five-planar optical waveguide structure will be replaced by the low concentration of organic gas prepared in the laboratory.The gas concentration variations will lead to a change of the effective refractive index of the waveguide structure.Finally,a linear CCD image acquisition system is used to collect the images of interference fringes.Studying the fringe movement with a change of the gas concentration will lay a foundation for the subsequent improvement of the optical waveguide gas sensor.