The Research Of High Performance Microwave Photonic Link System

Microwave photonics is an interdisciplinary study of the interaction between microwave signals and optical signals,combining the advantages of microwave and lightwave,which is considered as an important way to help break through the electronic bottlenecks.As an important part of microwave photonics,Microwave photonic links(MPL)are widely used in satellite communication and broadband wireless access networks.Therefore,how to improve the performance of MPL is one of the research focuses of microwave photonics.As a parameter to measure the input power range,the dynamic range is one of the most important parameters of MPL.However,existing electro-optic modulators are essentially nonlinear devices.The third-order intermodulation(IMD3)introduced by nonlinear modulation would cause the crosstalk between the adjacent channels and seriously affect the communication quality.The IMD3 is the main limiting factor of the dynamic range.In response to the above problems,this article focuses on the following work.1.The mathematical model of the indirect modulation link is established.The main performance indicators of MPL are introduced,and the influences of the component parameters are discussed.2.The linear method based on power adjustment scheme is proposed,and verified by simulation.This method can effectively suppress the IMD3 component of MPL and improve the dynamic range.3.The linear method based on phase adjustment scheme is proposed,and verified by simulation and experiment.According to the IMD3 elimination mechanism,the whole phase combinations which can suppress the IMD3 are found.On the basis of improving the dynamic range of MPL,the practicality and scalability of the method are greatly improved.4.The performance differences between these two methods and ordinary modulation link are comprehensive analyzed.It not only compares the improvement effect of these methods on dynamic range,but also analyzes their impact on other performance in detail.Based on the above work,this article has achieved the following results.This article proposes two linear methods which can improve the dynamic range of MPL:the linear method based on power adjustment scheme and The linear method based on phase adjustment scheme.Both of these methods can effectively increase the dynamic range of MPL,so as to improve the communication quality and increase the signal transmis sion distance.