Investigation Of Reconfigurable Optical Filters And Its Applications In Microwave Photonics

With the incresing of optical communication capacity,the demands for optical signal processing systems are increased.As one of the basic components in signal processing system,the optical filter also needs to provide various filtering functions and broad applications.However,traditional filters are often designed with single filtering function,which leads to the fact that a large number of filters are used in optical processing systems,thereby increasing the cost,size and complexity of the system.On the other hand,tunable and reconfigurable filters have attracted more and more attention because they can provide flexible filter shapes.The tunable and reconfigurable filters are beneficial to reduce the complexity and cost of the system,and realize miniaturization and integration of the system.optical and microwave signal processing systems is.In this thesis,the research of the reconfigurable optical filter and its application in microwave photonics are studied based on the analysis of the silicon-based microring resonator in the complex plane.The main work of this article includes the following two aspects:(1)The response of the microring resonantor is analyzed and five properties of the microring resonator response are proposed and proved in the complex plane coordinate system.The micirring resonator coupled Mach-Zehnder interferometer is designed based on the silicon-on-insulator platform.A real all-pass filter is successfully realized based on the lossy waveguide,which is a supplement to the types of optical filters.Its application is also studied,and a tunable broadband microwave photon phase shifter with simultaneous low power variation and large phase shift range is realized.Further,a general model for implementing optical all-pass filters is further proposed,and the all-pass conditions are theoretically derived.(2)Based on the analysis of the microring resonator properties in the complex plane,the microring resonator coupled MZI structure in(1)is used to implement an optical filter switchable between bandstop and bandpass responses,and the loss and bandwidth characteristics of the filter are theoretically analyzed.The feasibility of the switchable filter is verified by experiments.Applying the optical bandstop filter to microwave photonics,a microwave photonic bandstop filter with ultrahigh rejection ratio and narrow bandwidth is successfully realized.The feasibility of realization of the microwave photonic bandpass filter based on the optical bandpass filter is discussed.