Pressure Sensing Structure Based-on Two-Dimensional GaAs Photonic Crystal Considering Temperature Influence

The photonic crystal pressure sensing structure is an optical device based on the characteristics of photonic band gap and photon localization.Based on the previous work of our team,the pressure sensitivity and accuracy of the pressure sensing structure are further improved by considering the influence of ambient temperature.The prototype pressure strain sensing structure and tensile strain sensing structure with high practicability,sensitivity,accuracy and different pressure measurement ranges are realized.Among them,the measurement range of the pressure strain sensing structure is 0-2GPa,and the sensitivity and accuracy are 15.045 nm/GPa and 0.0052 GPa respectively.The measurement range of the tensile strain sensing structure is 0-1 ?N,and the sensitivity and accuracy are 1.214 nm/ ?N and 0.396 ?N,respectively.COMSOL muitiphysics 5.4 is used for design and simulation,and the band characteristic of photonic crystals is analyzed in combination with rsoft2013.The specific work is as follows:Firstly,a two-dimensional photonic crystal filter is designed to analyze the change of the filter's optical filtering performance under the effect of pressure and temperature.It is found that when the pressure and temperature increase at the same time or increase separately,the peak value of the filter mode will be linearly red shifted.According to the optical characteristics,a photonic crystal pressure sensing structure and temperature sensing structure are designed,which can be calculated more accurately by matrix method.The cylindrical photonic crystal is mainly studied in this paper,which makes use of gallium arsenide with good photoelastic properties for the dielectric cylinder material,and the background is air.The photonic band gap of photonic crystal in TE mode is obtained by the simulation of Rsoft software.In the design of the filter,in order to facilitate the subsequent design of the temperaturepressure sensing structure,the optical waveguide is designed as a rectangular waveguide: the cavity structure is formed by the design of symmetrical and non-uniform Ga As dielectric column,and the optimized structure quality factor can reach 6750,and the sensitivity of the pure pressure sensing structure can reach 15.88nm/GPa by using the photoelastic characteristics of the materials used.The accuracy is 0.0145 GPa,which includes the error caused by temperature change.The temperature sensing structure is designed based on the above photonic crystal structure.In order to combine with the pressure sensing part,the optical waveguide is designed as a hat structure,and the cavity structure is realized by backfilling four Ga As dielectric columns at the perfect lattice point at the outlet of the hat structure.The quality factor of the filter after parameter optimization can reach 7500.According to the thermal optical coefficient of Ga As,the temperature sensitivity of the structure is 0.007 nm /?.By combining the above two structures and considering the influence of different ambient temperature,a high-precision pressure strain sensing structure is designed.The structure is a single input and double-output filter,which is used for pressure output and temperature output respectively.Based on the coupled mode theory,the influence of cavity structure on photon transmission is analyzed.After optimization,the temperature sensitivity coefficients of the dual-output are /0.02nm?and /0.007nm?,and the quality factor of cavity 2 is 7869.The pressure sensitivity is 15.902nm/GPa,and the measurement accuracy is 0.0121 GPa by matrix method.The pressure sensing function with high sensitivity and precision is realized.For the temperature output,considering the low temperature sensitivity coefficient of the material used,PDMS material with high temperature sensitivity coefficient is introduced to improve the temperature sensitivity in order to better eliminate the temperature effect.The temperature sensitivity coefficient of the optimized dual-output with PDMS material is 0.019nm/? and0.0238nm/?,and the temperature sensitivity coefficient corresponding to the temperature output is increased by more than three times.The pressure sensitivity of the structure is 15.045nm/GPa,and the accuracy is 0.0052 GPa.The pressure sensing structure with higher accuracy is obtained,fully removing the temperature effect.In addition,considering the requirements of different measuring ranges,the tensile strain sensing structure is designed,and the influence of temperature is considered.The temperature sensitivity coefficients of the dual-output are 0.0066nm/? and 0.0197nm/?.The pressure sensitivity and accuracy of the sensor are 1.214nm/ ?N and 0.396 ?N.