Research On Refractive Index And Temperature Sensing Based On Two-dimensional Photonic Crystal Coupling Waveguide And Microcavity

Photonic crystal(PhC)has the characteristics of photonic bandgap and photon localization,which can control and manipulate the transmission of photons.Two-dimensional photonic crystal waveguide and microcavity structures provide an effective solution for sensing applications of high performance,miniaturization and integration.Photonic crystal sensor has the advantages of anti-electromagnetic interference,high sensitivity,high stability,small size,easy integration and so on.At present,there are still many problems to be solved in terms of sensitivity and integration of multiple sensing array structure based on the refractive index and temperature sensing of the two-dimensional photonic crystal coupling waveguide and microcavity.In order to realize the high sensitivity of two-dimensional photonic crystal refractive index and temperature sensing,structure design and performance optimization of refractive index and temperature sensors based on coupling waveguide and microcavity are achieved.The main research work and results are as follows:1)The influence factors of photonic crystal bandgap are analyzed by plane wave expansion method(PWE).The coupling forms of photonic crystal waveguide and microcavity are studied.2)Based on an optimized Y-type photonic crystal waveguide in this paper,photonic crystal microcavities are located via side-couple form in two output ports and in one input respectively.The microcavities in serial-parallel form a photonic crystal refractive index sensing array.The sensing array can improve the space utilization of photonic crystal sensor and achieve real-time independent detection of a variety of testing substances.Meanwhile,it can reduce the crosstalk between microcavities.3)Finite-difference time-domain method(FDTD)is used to design and optimize the two structures of photonic crystal temperature sensors.They can be applied to real-time temperature measurement in different micro-regions of on-chip laboratory and on-chip system.One structure is a photonic crystal T-type waveguide coupled to four different L3 microcavities to achieve a temperature sensing array with a maximum sensitivity of 45.84 pm/?.Resonant wavelength of the microcavity is shifted with temperature change in this sensing region while resonant wavelengths of other L3 microcavities are kept constant.Therefore,real-time temperature monitoring in different tiny areas is realized.Another structure is a photonic crystal waveguide coupled to two resonant microcavities on both sides by introducing a SU-8 negative photoresist microcavity.The temperature sensitivity of 124.8 pm/? is achieved,and the temperature measuring range is 0?150 ?.Moreover,the sensor structure proposed reduces the restriction of temperature sensing area.