All-optical Modulator And Characteristics Of Graphene-microfiber Waveguide

The atomic-thickness two-dimensional material graphene has a linear dispersion band structure,strong transit ability between carrier belt,thus can realize super-fast light and matter interaction in the broadband range,and it can freely attach on optics surface so as to realize the function of the photon structure,which showing a good application prospect and potential of a graphene light modulation,which is the most challenging one of the research direction and application prospects of the device.Due to the electro-optic modulation in transmitting terminal and receiving end exist the electricity-light-electric conversion,thus it shows poor compatibility,and the electronic bottleneck problem caused low modulation rate,if can use all-optical modulation mode,it will be able to bypass the parasitic response of the electronic circuit,and improve the modulation rate.Biconical silica oxide nano optical fiber directly obtained from the standard single-mode communication optical fiber by the method of melting.This light transmission form in the microfiber called evanescent field,therefore can easily realize the of light-matter interaction in the cone area of the microfiber,at the same time it can also realize the efficient link between the optical signals in the nano structure of and standard single-mode optical fiber communication systems.Based on the above background,this paper presents a study on the all-optical modulator of graphene-microfiber waveguide.Use of the strong evanescent field of the transmission light in the microfiber,we employed graphene films laid on the microfiber waveguide's surface,which can realize the interaction of light and graphene.This paper mainly explores the graphene based microfiber compound preparation of all-optical waveguide modulator.Firstly,we researched the optical transmission characteristics of microfiber,the existing preparation methods and the preparation methods of the microfiber that used in this paper.Secondly,the preparation,etching and transfer of graphene films were studied,and the preparation methods of the modulator used in this paper were discussed in detail.The third chapter of this paper mainly introduces the research of all-optical modulation by the polarization-dependent graphene microfiber waveguide,we first introduced the working principle of graphene all-optical modulation,and on this basis,we simulated the light in a waveguide with different polarization under the condition of the mode field distribution and interaction between light and graphene,and by constructed the polarization-dependent modulation system and did the experimental measurement,the result showed good effect on the light intensity modulation,realized the signal light modulation depth of the highest 20.86 dB.Finally,the modulation rate of the signal light 5.13 KHz was realized by using the chopper of mechanical chopper to study the temporal response characteristics of graphene microfiber waveguide's intensity modulation.In the fourth chapter of this paper,the microfiber diameter and number of graphene film related to the light intensity modulation were studied,and based on the different diameter of microfiber mode field distribution of the waveguide,we did the numerical simulation,and according to the simulation results of different diameter of the waveguide,laying the number of graphene films,covering different lengths of graphene film waveguide,we did all-optical modulation experiment tests respectively,and the experiment results were analyzed,researched the all-optical modulation characteristics of waveguide.Generally speaking,in this paper,based on graphene microfiber composite waveguide modulator in principle,preparation process,the experiment testing,performance,etc,which not only expand the application in the field of fiber optics and graphene photonics potential,but also provides a new way for the future development of optical information processing.