The Oretical Study On Electro-optic Regulation Properties Of The Graphene-coated Fiber And Fiber Devices

With the rapid development of optical information transmission and processing speed, the miniaturization, integration and low energy consumption of the fiber devices are the development trend of the optical fiber communication technology. Graphene has ultrahigh carrier mobility, ultrafast relaxation process, tunable Fermi level, and could absorb a wide frequency range of the incident light, so it is very suitable for the design of fiber devices. Here a novel graphene-based optical fiber structure is first proposed with graphene coated on the inner wall of the central airhole of the hollow optical fiber and photonic crystal fiber. A finite element method is adopted to analyse the modulation, filtering and polarization properties of the structure. The main contents of this paper are as follows:Firstly, combined the development history of the communication technology, the paper introduces the reaearch purpose and significance, then based on consulting a large number of domestic and foreign related literature, the paper reviews the research progress of the graphene-based fiber devices and summaries the way to combine graphene and optical fiber.Secondly, this paper analyses carefully the linear optical absorption and electro-optic modulation property of graphene which are detemined by the band structure of graphene, and then introduces the analytical method and numerical method which are adopted to analyze the transmission property of the optical fiber, specially introduces elaborately the finite element method, and further gives the simulation process of the software.Thirdly, a novel modulator model based on graphene-coated hollow optical fiber is proposed, and a finite element method is adopted to study the mode field distribution and electro-absorption property, then discuss the influence of air-hole’s radius, the number of graphene layers and the buffer layer on the performance parameters of the fiber modulator.Finally, three kinds of fiber devices model based on graphene-coated photonic crystal fiber are proposed. The first one with graphene coated on the inner wall of the circular central core, is to study the dependence of the fiber loss on the chemical potential and its modulation property, which could be used as eletro-absorption modulator; the second one with graphene coated on the inner wall of the circular central core, is to study the dependence of the fiber loss on the wavelength and its filtering property, which could be used as band-rejection filter. The third one with graphene coated on the inner wall of the elliptical central core, is to study the dependence of the TE mode and TM mode loss on the chemical potential and its polarization property, which could be used as fiber polarizer. The influences of the fiber’s structural parameters and graphene’s material parameters on the performance parameters of fiber devices are simulated with finite element method.