石墨烯—微纳光纤复合结构的非线性光学特性研究

发布时间：2018-06-06 11:10

本文选题：石墨烯 + 微纳光纤　；参考：《浙江大学》2015年硕士论文

【摘要】：石墨烯自从被发现以来,因其独特的二维结构以及光电特性,受到了广泛关注。特别是,石墨烯具有超高的非线性系数,是一种极具潜力的超紧凑非线性光学介质。因此,本文将石墨烯和微纳光纤相结合,形成石墨烯-微纳光纤复合结构,通过理论建模及数值仿真,对其非线性光学特性加以分析。在总结石墨烯波导的研究进展基础上,本文结合微纳光纤传输理论及石墨烯光学特性理论,建立了石墨烯-微纳光纤复合结构的非线性参量过程理论模型。仿真计算表明,复合结构同时具有高非线性系数和高损耗值,因而提出利用FOM参数表征该复合结构的非线性特性。通过对微纳光纤直径进行优化,针对通信波段1550nm以及10w的入射光峰值功率,FOM参数在微纳光纤直径为0.75μm时达到其最大值0.0083 W-1。仅在26.2μm长的复合结构中,最高转换效率可达-25.2dB,转换带宽达到400nm,而且将入射泵浦光放置在零色散波长附近(980nm),转换带宽能够达到780nm。可见,通过在微纳光纤上包覆石墨烯形成石墨烯-微纳光纤复合结构,可以有效提升其非线性光学性能。本文分析了石墨烯化学势的变化对复合结构的影响。当化学势为0.5 eV时,石墨烯-微纳光纤复合结构在1550 nm波段将会发生狭缝效应,石墨烯层对光场的束缚作用大大加强。此时,在2μm量级长的复合结构中,仅需2mW入射功率,转换效率即可提高至1.6dB,但是因符合狭缝效应的波段很窄,带宽变得很窄,仅为4 nm。
[Abstract]:Graphene has attracted much attention since it was discovered because of its unique two-dimensional structure and optoelectronic properties. In particular, graphene has a high nonlinear coefficient and is a potential ultra-compact nonlinear optical medium. In this paper, graphene and micro-nano fiber are combined to form graphene micro-nano fiber composite structure. The nonlinear optical properties of graphene fiber are analyzed by theoretical modeling and numerical simulation. On the basis of summarizing the research progress of graphene waveguide, the nonlinear parametric process model of graphene micro-nano fiber composite structure is established by combining the theory of transmission of micro-nano fiber and the theory of optical properties of graphene. The simulation results show that the composite structure has both high nonlinear coefficient and high loss value. Therefore, FOM parameters are used to characterize the nonlinear characteristics of the composite structure. By optimizing the diameter of micro-nano fiber, the maximum value of 0.0083 W-1 is obtained when the diameter of micro-nano fiber is 0.75 渭 m for the 1550nm of communication band and the peak power of incident light at 10 w. Only in the 26.2 渭 m long composite structure, the maximum conversion efficiency can reach -25.2dB, the conversion bandwidth is 400 nm, and the incident pump light is placed near the zero dispersion wavelength, the conversion bandwidth can reach 780 nm. It can be seen that the composite structure of graphene and micro-nano fiber is formed by coating graphene on the micro-nano fiber, which can effectively improve the nonlinear optical properties of the fiber. In this paper, the influence of the chemical potential of graphene on the composite structure is analyzed. When the chemical potential is 0.5 EV, the slit effect will occur in the 1550 nm band of graphene micro-nano fiber composite structure, and the binding effect of graphene layer on the light field will be strengthened greatly. At this time, the conversion efficiency can be increased to 1.6 dB in the composite structure with 2 渭 m order of magnitude, only need 2mW incident power, but due to the narrow band according to the slit effect, the bandwidth becomes very narrow, and the bandwidth is only 4 nm.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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