Research On Transmission Characteristics And Temperature Sensing Characteristics Based On Microring Resonator

With the rapid development of information technology,the sensing technology as one of its pillars has developed rapidly due to the task of extracting information in the real world.Temperature sensors have been widely used in various fields such as industrial production,medical diagnosis,agricultural monitoring,and daily life.People's requirements for the miniaturization,integration and high performance of sensor devices are getting higher and higher,and the micro-optical sensor devices using optical waveguides as media due to their higher sensitivity,stronger resistance to electromagnetic interference and good integration have gained extensive research and attention.As an important component unit in integrated optics,micro-ring resonators have the advantages of compact structure,flexible design,and high integration.The optical sensor device detects the change of the external environment index through the function of the evanescent field on the surface of the optical waveguide.The application of silicon-based micro-ring resonators is more concerned in this aspect because they have a high quality factor,low cost,and good thermo-optic effect.In this thesis,the transmission characteristics and temperature sensing characteristics of other composite structure resonators based on the silicon-based microring resonator were studied.Around improving its measurement range and detection sensitivity,an improved structure with better performance was proposed.The scattering matrix model was used for theoretical analysis,and the software based on the finite difference time-domain method was used to simulate its transmission characteristics.The main work is as following:(1)The related theory and working principle of the micro-ring resonator are introduced,and the transmission characteristics of its basic structure are studied by using the transmission matrix method.Three-dimensional structural models of these structures are established and their transmission spectra are simulated.Simultaneously,the influence of the structural parameters of the resonator on its characteristic indexes and the propagation path of the optical signal when resonance occurs are simulated and analyzed.(2)The composite structure based on the micro-ring resonator is studied,and an improved slot-type feedback coupled micro-ring resonance structure is proposed based on the existing research.First,the transfer matrix method is used to analyze the output function expression of the structure,and a comparison is made between before and after the structure improvement.Simulation results show that when the length of the feedback waveguide is an integer multiple of the perimeter of the microring,the free spectral range is doubled compared to the microring resonator with the same structural parameters,and the extinction ratio can reach 30 dB.At the same time,the sensing theory of the micro-ring resonator is analyzed,andthe temperature sensing conditions of different parts of the feedback-coupled micro-ring resonator are modeled and simulated.(3)The Fano resonance in the structure of a one-dimensional crystal microcavity etched by a rectangular straight waveguide coupled with a microring resonant cavity is studied.According to the characteristics of the asymmetric spectral patterns generated by the coupling of the two structures,the transmission characteristics of the microring resonator and the one-dimensional photonic crystal microcavity are analyzed respectively.The mechanism of the asymmetric spectral pattern is explained by the coupling of their resonance states.That is,Fano resonance is formed by the light interference of the discrete state and the continuous state in these two structures.At the same time,the influence of the structural parameters of the device on transmission characteristics and temperature sensing characteristics are analyzed.