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With the development of today's information age, information perception, acquisition, conversion, transmission and processing of functional devices - sensors, has become the various applications, especially in automatic detection, automatic control system indispensable technology tools. Access to various information sensors undoubtedly \At present, industrial automation, energy, transportation, fire forecasting, security and defense, environmental protection, health and other aspects of the development of the various sensors. Thesis introduction part, starting from the sensor and sensor technology, tells the story of chemical sensors and their classification, the classification of gas sensors and a variety of semiconductor gas sensor working principle and characteristics. And the future development of optical waveguide gas sensors is reviewed introduced waveguide gas sensor characteristics and classification. Theoretical part of the paper, introduces the waveguide overview, light refraction, total reflection of light, planar waveguide, prosperous and lost wave theory of light in planar waveguide coupling principle. Experimental part of this paper, the use of the superior characteristics of the optical waveguide sensing element to SnO2/La2O3, SnO2/Sb, SnO2/ZnO screening for sensitive reagent, developed detection of volatile organic compounds and acid gases with high sensitivity optical waveguide chemical sensors. Experimental section is divided into three chapters: 1. Developed of La2O3 doped SnO2 composite films by X-ray diffraction (XRD) method, Fourier transform infrared spectroscopy (FT-IR) method to characterize the phase structure of the film, and The film by UV - visible spectroscopy. Experimental results show that with increasing the content of La2O3, the absorbance of the film also increases. Containing 3.0% La2O3 SnO2 thin film and the role of the measured gas after the 630-680nm at its maximum absorbance change, so choose 3.0% La2O3 of SnO2 composite film as sensitive reagents fixed on the surface of tin-doped glass optical waveguides, respectively of volatile organic gases and acid gases were detected and discussed the sensing principle. 2 were prepared using dip different mass fraction of Sb doped ions SnO2 composite membrane, an X-ray diffraction (XRD) method to characterize the phase structure of the film, can be obtained from the XRD results, the grain size of the film As the content of Sb increases. And the film by UV - visible spectroscopy. The experimental results show that with the increase in the amount of antimony-doped, the light transmittance of the film decreases. Containing 0.5% Sb and SnO2 thin film role after the measured gas at 670nm at its greatest change in light transmittance, so choose 0.5% Sb in SnO2 composite film as a sensitive reagent fixed on the surface of tin-doped glass optical waveguides, respectively, volatile organic gases and acid gases were detected and discussed sensing principle. Room temperature, the gas sensitive element xylene selectivity is better. Followed by benzene, toluene gases. 3 developed doped ZnO, SnO2 composite films by X-ray diffraction (XRD) method to characterize the phase structure of the film. And the membrane by UV - visible spectroscopy. Experimental results show that with the increase of content of ZnO, the transmittance of the film decreases. Containing 1.0% ZnO and SnO2 thin film role after the measured gas at 670nm at its greatest change in light transmittance, so choose 1.0% ZnO composite films of SnO2 as sensitive reagents fixed on the surface of tin-doped glass optical waveguides, respectively of volatile organic vapors and acid gases were detected and discussed the sensing mechanism.
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