Arrayed Waveguide Grating Demodulation Photon Integration And Its Application In Wearable Body Temperature Monitoring

So far,most of the development of wearable sensors are based on electrical sensors.These sensors are generally sensitive to electromagnetic interference by measuring the changes of electrical properties such as resistance,current and voltage.Fiber Bragg grating(FBG)is a very important optical device,which has achieved great success in the application of FBG sensing.Compared with wearable electronic sensor,optical fiber sensor has the advantages of intrinsic safety,no electromagnetic interference,high sensitivity,light weight,small volume,easy reuse(Networking),etc.,especially the compatibility between optical fiber and fabric fiber,so that it can be woven into fabric,forming a real wearable "fabric sensor",improving the wearing comfort.Therefore,optical fiber sensor is an ideal sensor for wearable applications.In this thesis,the silicon-based photon integration of FBG demodulation system and wearable application of FBG sensor are studied.An 8-channel silicon-based fiber grating demodulation system is designed.The optical path of the system is mainly composed of laser source,1×4 input grating coupler,2×2 MMI coupler,Edge coupler,1×8 arrayed waveguide grating and 8-channel photodetectors.The edge coupler and the input grating coupler are analyzed and optimized by the finite difference time domain method.The maximum coupling efficiency of the edge coupler is-0.7d B,the input grating coupler is-3.9d B and the size is reduced to 1/6 of the traditional grating coupler.The array waveguide grating and MMI coupler are simulated and optimized by the beam propagation method.The input and output waveguides are designed with the inverted cone structure.The additional loss of the device is reduced from 1.09 d B to 0.46 d B when the device size is constant.Through the alignment platform of micro fiber coupling,the vertical and horizontal coupling packaging is completed.In order to ensure the movement of the sensor and the fabric warp and weft is in harmony,the fiber Bragg grating sensor is embedded into the clothing.The experimental results show that the wavelength demodulation range is 1545.30-1560.50 nm,the temperature measurement error is ±0.1?,the wavelength demodulation accuracy is ±1pm,and the wavelength resolution is 1pm.The research in this paper will promote the wearable application of FBG demodulation system,and lay a foundation for the further development of silicon-based optical integration and interconnection technology.