Study On The Key Technologies Of Photonic Crystal Waveguide Sensing And Demodulation

The photonic crystal structure has the unique light control mechanism and flexible structure design,which can meet the design requirements of integrated sensors.Based on the triangular lattice air hole photonic crystal,photonic crystal 1×2 beam splitter and slot waveguide dual-parameter sensing model was designed by combined with photonic band gap characteristics,coupling characteristics and photon localization characteristics.Then the light control sensing mechanism and demodulation method of proposed models based on SOI material are studied.The main research contents of this dissertation are as follows:(1)Based on the photonic gap characteristics,the optical properties of the triangular lattice air holephotonic crystal waveguide structure are discussed.The energy band characteristics of different photonic crystal structures are analyzed by plane wave expansion method.The optical wave propagation characteristics are calculated by the finite difference time domain method.Finally,the transmission characteristics,frequency selection characteristics and coupling characteristics of photonic crystal waveguides are studied.(2)Based on the basic symmetrical structure of Y-waveguide,a 1×2 photonic crystal beam splitter is designed and analyzed.In order to optimize the output light wave characteristics,the numerical parameters are used to explore the size parameters and position of the fine-tuning structure.Finally,the transmitted light wave energy flow is evenly divided by achieving perfect impedance matching,and each output port obtains a light wave with a lower loss in a specific frequency band.(3)The dual-parameter sensor of methane and temperature based on photonic crystal waveguide is designed and optimized by introducing two slotted photonic crystal waveguides infiltrated with the material sensitive to methane in perfect square-lattice air holes.Then the sensing model of photonic crystal waveguide is established to analyze the sensing characteristics of methane and temperature.The results show that the center wavelengthes of the two transmission peaks have a blue-shift with the increasing of methane gas concentration,while the center wavelength of two peaks have a red-shift with the increasing temperature.Among them,the methane sensing sensitivity of slot1 can reach 1.2nm/% and the temperature sensitivity is 1.69nm/°C.The methane sensing sensitivity of slot2 can reach 1.08nm/% and the temperature sensitivity is 1.66nm/°C.Meanwhile,combining the two-parameter matrix method can solve the problem of sensing cross-sensitivity...