Optimization Of Optical Waveguide Structures For High-throughput Biosensors

Optical biosensor refers to a device that uses light signals as a carrier and can be used to obtain biomolecular interaction information.When the light signal passes through the device's biosensor unit,its characteristics will change.Detecting and analyzing this change can realize the biosensor function.As a medium that can be used for optical signal transmission,optical waveguide has the advantages of simple structure,small size,light weight and resistance to electromagnetic interference.It is widely used in the field of sensing.At present,most of the researches on biosensors using optical waveguides use single-sensor point structures as sensing units for biomolecular interactions,but there are few studies on multi-point or even high-throughput optical waveguide sensing structures.To this end,this paper proposes an optical waveguide structure(including Bragg gratings)that can be used for high-throughput biosensing functions.The optical waveguide structure is divided into multiple segments,and each segment consists of a biological layer and an abiotic layer.The layers are sensing units(places where biomolecular interactions can take place).The main content of this paper is to explore the sensitivity characteristics of different structures or structural parameters based on the multi-segment structure.Here is a brief overview of the work done in this paper: 1.Establish a sensing structure model,and give the sensitivity characteristic analysis method based on the sensing structure model.This section mainly introduces the theoretical basis of optical waveguide structure optimization of high-throughput biosensors.2.Using the analysis method of sensitivity characteristics,the relationship between the biological layer parameters and wavelength and the effective refractive index of the structure core mode was numerically analyzed using a computer.Then,the multi-sensor model based on the Bragg grating structure is optimized,and the grating structure with stable sensitivity change and larger value is selected.Finally,based on the grating structure,the sensitivity characteristics of several structural parameters of the sensing structure are explored.3.Explore sensitivity characteristics of other structural models under multi-segment structures,such as the sensitivity characteristics of the related parameters of the single-sensor point structure in the multi-segment structure,and explore the sensitivity characteristics of the multi-sensor point structure and the length of each layer sensitivity characteristics of randomly changing structural models.According to the analysis of theresults,the following main conclusions can be drawn: Changes in the refractive index of the biological layer will affect the effective refractive index of the core mode and will change faster as the refractive index of the biological layer increases.Among the several grating structures explored,the sensitivity characteristics are most suitable when the phase shift grating is used as the basic structure of the model.Similarly,different structural parameter values will also affect the response spectrum(amplitude spectrum and phase spectrum)of the sensing model,thereby affecting the sensitivity characteristics of the structural model.Considering that changes in some structural parameter values have a greater impact on the amplitude spectrum,Therefore,it is necessary to combine the overcoupling conditions of the grating to optimize the selection of parameter values.When exploring the sensitivity characteristics of different structures,it is necessary to consider a variety of possible situations,such as the location of the refractive index change of the biological layer.At the same time,it is also necessary to consider the different situations of the refractive index change of the biological layer(each segment changes simultaneously or individually).The research in this paper can provide a theoretical basis for the design and optimization of corresponding high-throughput biosensor structures,and provide a certain reference value for the subsequent design and optimization of optical waveguide structures of other high-throughput biosensor structures.