| In the development of information technology and communication technology,information acquisition,information transmission,and information processing are processed all the time.And the most critical technology in the information collection is sensing technology.Sensing is the process of obtaining information from natural sources and processing them.Compared with traditional sensors,photonic crystal sensors have the advantages of high sensitivity,low mode volume,easy integration and anti-electromagnetic interference.At the same time,photonic crystal sensor is an optical device,which also plays a big role in promoting all-optical integration of communication.In photonic crystal sensing,photonic crystal microcavities have many advantages that traditional photonic crystal sensing does not have due to its structural diversity,such as high Q factor,low mode volume,and easy integration.First of all,the structure of the nanocavities is variable,photonic crystal nanocavity can be divided into HO,H1,Ln and other linear nanocavities,and some orbital annular cavities,etc.The diversity of the structure brings about the diversity of performance.The high locality of the nanocavity for photons makes it possible to optimize the photonic crystal microcavity to obtain a high Q value and a low mode volume.A nanocavity is independent of the entire photonic crystal structure,that is,we can integrate into other photonic crystal structures according to the corresponding proportions of the structure by coupling with other structures,and retain its unique excellent characteristics.Accordingly,this paper proposes a photonic crystal structure for two-parameters sensing by means of two different nanocavities.The first step in the design is to design and optimize a two-dimensional photonic crystal microcavity that can achieve refractive index sensing and temperature sensing.After many simulations and comparisons,we finally chose the L3 microcavity and the L4 microcavity as the alternative structures for sensing,because the high Q and high transmission are two important in sensing research.Performance.According to the traditional optimization method for the photonic crystal microcavity,that is,adj usting the radius and position of the air hole around the microcavity,the Q factor of the L3 microcavity can reach 15860,and the Q factor of the L4 microcavity can reach 7087.In order to achieve dual-parameter simultaneous sensing,we use a photonic crystal waveguide to couple the two microcavities.Due to the interaction between the two microcavities,the Q factor of the L3 microcavity reaches 16330.8,and the Q factor of the L4 microcavity reaches 8358.21.At the same time,the transmission intensity did not change a lot.It can be seen that the crosstalk between the two microcavities is very small.In order to further quantify the crosstalk between the two microcavities,we have done a series of simulation studies,and the results show that the maximum crosstalk between the two microcavities is 4.51dB,further illustrating low crosstalk between microcavities.The second part of the design is the sensing simulation.For this part of the study,we chose the refractive index and temperature as two parameters for the study.First of all,the refractive index is a key parameter in both bio-detection and chemical detection.Because the solution concentration and particle size are reflected in the change of refractive index,which makes the application range of refractive index is wider.Secondly,Temperature is a parameter that must be considered and easily ignored in general inspection.It is easier to control the rigor of the temperature control.Through the relevant simulation research,the corresponding sensitivity is obtained by using the wavelength shift of the detected resonance peak.For the L3 microcavity,the refractive index sensitivity is 111 nm/RIU,the temperature sensitivity is 74 pm/K;for the L4 microcavity,the refractive index sensitivity is 107 nm/RIU,and the temperature sensitivity is 76 pm/K.The sensitivity matrix thus obtained is a full rank matrix,which also guarantees the theoretical feasibility of simultaneous sensing of dual parameters.The last part of the article is to analyze the error problems that may be encountered in the actual experiment,and then analyze the stability of the structure.This part mainly considers the influence of the deviation of the air hole radius on the structure Q value and sensitivity.By adding a radius deviation of-5%-10%to the air holes,the corresponding Q factor and sensitivity change are compared.The final results show that the deviation from sensitivity is kept within the range of 1%to 3%,which is within an acceptable range,indicating that the structure has strong stability. |
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