| In recent years,resonant micro-optic gyroscope has gradually became one of the popular topic at home and abroad.The resonant micro-optic gyroscope based on the Sagnac effect has great potential for integration and miniaturization.Light source,photodetector,modulator,resonator and other key components could be integrated on a chip with the development of semiconductor processing technology,so that the resonant micro-optic gyroscope has advantages of small size,all solid and shock resistance.As the key sensing element,optical waveguide resonator parameters seriously affect the resonant micro-optic gyroscope performance.In this paper,the optical transmission characteristics of the optical waveguide resonator has been analysed,and the key parameters of the resonator has been discussed.A systematic study was carried out aiming the key problems about the low quality factor of the waveguide resonator and the lack of optimization of the structural parameters of the resonator,a design method of silica waveguide resonator was proposed to fabricate high quality factor waveguide resonator.The main research contents can be summarized as follows:(1)The design and fabrication of a high Q Ge-doped silicon dioxide waveguide resonator was presented.According the requirements of application of resonant micro-optic gyroscope,the parameters such as the depth,width and the maximum value of the curvature of bend waveguide wre calculated using the effective refractive index method and the beam propagation method.Germanium doped silica optical waveguide resonators were fabricated on a silicon substrate with plasma enhanced chemical vapor deposition,photolithography and reactive ion etching technologies.The size of cross section of the optical waveguide was 6 ?m × 6 ?m,the transmission loss was 0.017 dB/cm.The waveguide resonator wass a runway structure with a size of 2 cm × 3.6 cm.The testing system for the resonant curve of the waveguide resonator has been constructed,and the test result showed that the quality factor of the germanium doped silica waveguide resonator was as high as 107.(2)A method for optimizing the structure of the optical waveguide resonator was proposed.According to the principle of signal detection of resonant micro-optic gyroscope,the optimal design parameters of the optical waveguide resonator were presented under the under-coupling condition and the resonance depth is equal to 0.75.Through the analysis of the resonant cavity,the resonance depth and the full width at half maximum of the waveguide resonator were different under different coupling conditions.Compared the trend of the quality factor and the resonance depth under different coupling conditions theoretically and experimentally,the characteristic structural parameters of the optical waveguide resonator were obtained.(3)The design of double-loop waveguide resonator was proposed according to the relationship between the cavity length and the full width at half maximum.This structure could improve the quality factor of the waveguide resonator by increasing the cavity length.An experiment of a fiber ring resonator welding with different length fiber was carried out to confirm the relationship between the cavity length and the full width at half maximum.The highest result was obtained with a fiber ring resonator with a cavity length of 100 m and a factor of up to 6.74×109.A double loop waveguide resonator with a cavity length of 21.6cm was also designed and fabricated on a silicon substrate,testing its quality factor up to 2×107.In this paper,silica waveguide resonators with quality factor up to 107 were prepared,an optimization method and multi-loop waveguide resonator structure were proposed for the resonant micro-optic gyroscope application.These work solved the key technical problems of the waveguide resonator,and lay a good foundation for the research of the resonant micro-optic gyroscope. |
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