Design And Performance Analysis Of Temperature And Refractive Index Dual-Parameter Sensors Based On Single Photonic Crystal Nanobeam Multimode Microcavity

Photonic crystals generally refer to man-made periodic dielectric materials.Due to their excellent optical properties,photonic crystals have been applied in many optical fields.Photonic crystals have the advantages of small footprint,high sensitivity,and small mode volume,so they have significant advantages in the field of on-chip integrated sensing.After years of development,a large number of sensors based on one-dimensional photonic crystal nanobeam microcavity have been developed.However,with the complexity of sensor application scenarios in recent years,the detection results are affected by multiple parameters at the same time,so the multi-parameter sensor arises at the historic moment.Due to the thermo-optical effect,the temperature will change the refractive index of the medium,which indirectly causes the shift of resonant wavelength.Therefore,it is necessary to accurately distinguish the influence of the temperature change and the external environment refractive index change on the sensor.In order to further improve the performance of the sensor and realize the dual-parameter detection of temperature and refractive index,several dual-parameter sensing models based on the single nanobeam multimode microcavity of one-dimensional photonic crystal with high performance were designed and analyzed in this paper.The main research results of this paper include:Firstly,a high-sensitivity air-mode nanobeam microcavity is designed.The multimode microcavity structure consists of bo wtie-shaped hole arrays etched on a silicon waveguide.The microcavity structure is formed by linearly tuning the radius of the bowtie-shaped hole.The temperature and refractive index are measured by measuring the wavelength shift of the resonance peaks of the fundamental mode and the first-order mode.The mode field is localized strongly at the tip of the bowtie-shaped hole,which reduces the mode volume.Therefore,the sensitivity of the sensor is enhanced.The RI and T sensitivities of the fundamental mode are 473nm/RIU and 31pm/K respectively,whereas those of the first-order mode are 487nm/RIU and 29pm/K,respectively.Simulation results show that the sensor can effectively detect temperature and refractive index simultaneously.Secondly,a slotted nanobeam multimode microcavity was designed by quadratically modulating the hole width and the lattice constant.The cavity supports the air mode and dielectric mode at the same time.The dual-parameter sensing is realized by jointly measuring air and dielectric mode resonance wavelength shifts and constructing a two-dimensional sensitivity sensing matrix.Because the mode field of air mode and dielectric mode is localized in the air hole region and slot region respectively,the sensitivity difference of the two modes is obvious,and the sensor has high sensitivities and good decoupled performance.The refractive index sensitivity and temperature sensitivity of air mode are 421nm/RIU and 58pm/K,respectively,and those of dielectric mode are 706nm/RIU and 46pm/K,respectively.Simulation results show that the sensor can accurately detect temperature and refractive index simultaneously.Thirdly,another slotted nanobeam multimode microcavity which supports air and dielectric mode was designed by linearly modulating slot width and the hole width.The dual parameter sensing of temperature and refractive index is carried out by jointly measuring the resonance shifts of fundamental air mode and fundamental dielectric mode.The sensor also has high sensitivity and good decoupled performance.Meanwhile,the sensor has a compact footprint of less than 12×0.75?m2(length × width).The RI and T sensitivity of air mode are 399nm/RIU and 56.3pm/K,respectively,and those of dielectric mode are 705nm/RIU and 43.3pm/K,respectively.Simulation results show that the sensor can accurately detect temperature and refractive index simultaneously.In this paper,a variety of high-performance one-dimens ional photonic crystal single nanobeam multimode microcavities were designed.By establishing temperature and refractive index dual parameter sensing models,the anti-external interference,sensitivity,and other characteristics of the sensors were analyzed and studied.The simulation results show that the proposed dual-parameter sensor has a simple structure,and its performance has been improved.Therefore,it has a broad application prospect and is worthy of further study.