Study On The Sensing Characteristics Of Plane Photonic Crystal Waveguide

Due to the specific control light mechanisms and flexible structure characteristics, photonic crystal structure become more suitable for requirements of micro sensor design. In this thesis, we choose silicon dielectric rod array photonic crystal structure as study object. Based on interest photonic band gap effect of photonic crystal, we proposed various photonic crystal sensors analytical models with different structures while studying deeply on photonic crystal waveguide coupling characteristics, bandgap guiding light properties, photonic crystal micro cavity photon localization characteristics, By analyzing the system sensing mechanism, the application of this sensing structures in relevant sensing field is verified. The research contents of this thesis are mainly included as following:Based on square lattice with rods array photonic crystal fundamental structure, light controlling properties and transmission characteristic of photonic crystal waveguide and nano-cavity are analyzed emphatically. According to self-imaging theory, we study on waveguide-waveguide and waveguide- cavity coupling mechanism which provide scientific rationales for plane photonic crystal waveguide sensors theoretical researching and design.On the base of defect effect in photonic crystal on bandgap, a two-dimensional photonic crystal cross-waveguide symmetrical structure consisting of dielectric rods array is designed. The optical field pattern and transmission spectra are analyzed by finite difference time domain method. A sensor model sensitive to stress along three directions was proposed via reasonable parameter optimizing. By numerical calculations we reach strain sensing sensitivity and linear range of this cross-waveguide.Based on coupled plane photonic crystal waveguides, the effective side-coupling between directional coupled waveguides and surrounding defect cavities gives flexibility in the choice of the sensing monitoring band. By using micro-machined cantilever, the transmission spectra of photonic crystal sensor under external force is analyzed by finite difference time domain(FDTD) method. Finally, we proposed a dual-channel sensing method to eliminate the cross-sensitivity effect between the strain and ambient temperature for optical signal sensing.