Optical Waveguide Sensor Based On Micro-Ring Resonator

Optical biosensors have played an increasingly important role in medical,food safety,environmental testing and other fields due to their advantages such as fast response rate,high sensitivity,and strong electromagnetic interference resistance.The passive waveguides based on the SOI platform have been widely used in the field of biosensing due to its small size,high integration,and excellent performance.However,its operating band(above 1100nm)has made the detection cost higher.Another kind of waveguides based on Si3N4 and SiON platform have developed rapidly in recent years.Its working band can cover visible light,and it is easy to integrate with silicon detectors,which greatly reduces the detection cost.Therefore,it has great development potential in the field of optical sensing.This thesis aims to realize the micro-ring resonance sensor with excellent performance on the SOI platform and Si3N4/SiON platform.This thesis starts from introducing the basic principles of the micro-ring resonator in detail.The transmission spectrum of the micro-ring resonator is analyzed by using a transmission matrix.The performance parameters and sensing principles are analyzed in detail.Then a novel sensing test method based on polarization vernier effect is proposed.Its feasibility and performance parameters are analyzed theoretically,and a comprehensive design on the SOI platform is proposed.The theoretical simulation shows that this detection method can improve the sensing sensitivity by an order of magnitude.Then the manufacturing process of silicon-based optical waveguide is introduced in detail,and a polarization-controllable microfluidic test system is set up.Finally,the performance of the micro-ring resonator based on the SOI platform and the Si3N4 platform is compared in detail,mainly analyzing the sensing sensitivity and temperature sensitivity.Then,a silicon oxynitride material is used to make the micro-ring resonator to realize the sensing experiment in the 850nm band.The single micro-ring resonator's sensitivity is 1 1.2nm/RIU.The sensitivity can be greatly improved by using the cascaded double-ring resonator,resulting from the Vernier effect.The test results show that the cascading double-ring resonator's sensitivity is 151.4nm/RIU,which improves the sensing sensitivity by 13.5 times.