石墨烯具有特殊的二维柔性结构,可调控费米能级特性和优异的光学、电学性能。利用有限元法，对覆石墨烯微纳光纤光场调控进行理论分析，通过改变石墨烯与缓冲层结构覆微纳光纤的角度，破坏光纤的对称性结构，使光纤具有双折射特性，双折射度大小与石墨烯覆盖角度有关；通过外加电压的方法改变石墨烯的化学势，可对光纤进行开关调控，由此设计出一种包覆石墨烯的微纳光纤电吸收型调制器并进行性能分析。通过数值分析可发现当覆盖光纤角度为270°时，1550 nm处双折射度可达1.23×10-3；电吸收调制器工作在1550 nm时，器件长度为18 μm，消光比为7 dB，3 dB带宽可达到927 MHz，插入损耗为0.58 dB。

Based on the special two-dimensional flexible structure，graphene has excellent optical and electrical properties. With the finite element method, we theoretically investigated modulation of the optical field of graphene covered microfiber. By changing the overlay angle, the symmetrical structure of fiber was destroyed to provide the microfiber with birefringence. The value of birefringence is a function of overlay angle. The chemical potential of graphene can be modulated and the light transmission of optical fiber can be switched by changing the external voltage. We designed a graphene covered microfiber based electrical absorption modulator and proceeded the performance analysis. Numerical simulations show that when the overlay angle is 270° and the incident wavelength is 1550 nm,the birefringence can be up to 1.23×10-3. When the electric absorption modulator works at the wavelength of 1550 nm, its length is 18 μm, the extinction radio is 7 dB, the 3 dB bandwidth reaches 927 MHz, and the insert loss is 0.58 dB.