Research On All Optical Modulation Characteristics Based On Graphene Coated Microfiber

The optical modulator plays an important role in optical fiber communication.In recent years,two-dimensional materials represented by graphene have attracted much attention due to their unique electrical,optical and thermal properties.Because requirements for optical devices are more and more integrated and miniaturized.The combination of the microfibers and graphene shows great advantages,which expands the application of fiber optics and graphene photonics.The research and application of electro-optical modulations and all-optical modulators based on graphene-microfiber composite structure in recent years are summarized.Based on the saturated absorption characteristic of graphene and the evanescent field characteristic of microfibers,the all-optical modulators are constructed and measured.The main contents are summarized as follows:Firstly,the background and significance of this subject are introduced.The electro-optic modulators and the all-optical modulators with graphene at home and abroad are depicted in detail.The contents are determined by comparing the different mechanisms and their advantages and disadvantages.Secondly,the basic characteristic of microfibers,graphene and the mechanism of all-light modulations are analyzed.The influence of graphene on the transmission characteristics of microfiber are studied through modeling the microfibers and microfibers coated graphene respectively.The influence of parameters,such as the wavelength of incident light and the radius of microfibers,on modulations depth and modulation efficiency are analyzed.Thirdly,the preparation method of microfibers coated graphene is studied.The parameter selection and the operation steps are described in detail,and the transmission spectrum of each preparation stage are analyzed.Graphene coated on microfibers is characterized by Raman and SEM respectively.Finally,the properties of linear and nonlinear absorption on graphene are studied.An all-optical modulator system based on graphene coated microfiber is built.The basic parameters,such as modulation depth and modulation efficiency,are analyzed by changing the wavelength of signal light.