Research On The Optical Waveguide Microcantilever Sensing

Nanomechanical sensors have been widely studied in the application of biological and chemical sensors because of their high sensitivity and integration.As a new nanomechanical sensing technology,the optical waveguide microcantilever sensor combines the cantilever structure in mechanical mechanics with the optical waveguide.When the surface of the cantilever is stressed in the static mode,the deflection will make the change of the optical power coupling between the optical waveguide cantilever and the output waveguide.The deflection of the cantilever can be obtained by detecting the variation of the output optical power of the structure.This detection technology has the advantages of high sensitivity and small size in nanomechanical sensing.Also,compared with other cantilever deflection detection methods,the detection technology has developed new features of easy integration,simple use,and fast detection response,which has received doubled attention.The main research contents and innovations of this article are as follows:（1）The structure and principle of the optical waveguide cantilever sensing are studied.The optical and mechanical models are established using COMSOL software.The two physical fields are coupled to analyze the working process,optical transmission and stress distribution of the device.The calculation method of the coupling efficiency and detection sensitivity of the device are deduced.（2）An improved optical waveguide microcantilever sensing structure is proposed.A buffer is provided at the junction of the input waveguide and the optical waveguide cantilever to reduce the optical coupling power loss by extending the input waveguide.The simulation proves that the improved structure can significantly optimize the detection sensitivity.（3）The improved optical waveguide microcantilever sensing structure is analyzed and the sensitivity is evaluated.The simulation proves that the improved structure can significantly optimize the detection sensitivity.Studies have shown that the optimum length of the buffer is 0.97μm at a cantilever thickness of 300 nm.In this configuration,the optical loss drops to about 40%and the sensitivity can reach 5.7×10^-49)8)^-1,which is 51.3%higher than the traditional structure.（4）The production process is designed for the improved optical waveguide microcantilever sensor.The design and realization of the corresponding control group and the photolithography mask are carried out.