Coupling Structure And Application Of Graphene With Microcavity And Microfiber

With the rapid development of society,optical devices have been widely used in many important areas of life.Such as optical system polarization,optical communication,sensors and other fields.In recent years,two-dimensional materials such as graphene have been widely used in optical research because of their good optical anisotropy,broadband,transparency,flexibility and fast response characteristics.The excellent properties of graphene not only have very important application prospects in coatings,energy,biomedicine,batteries and optoelectronic devices,but also have broad scientific research prospects in the field of composite materials.Therefore,in this paper,the graphene wrapped micro-fiber composite structure and the graphene-coupled silica microsphere structure are simulated,and the two structures are studied in high sensitivity sensing,all-optical modulation and optical polarizer respectively.The main work of this paper is as follows:Firstly,the development status of optical fiber in optical fiber sensing and microfiber structure all-optical modulation at home and abroad is analyzed.According to the development and application of devices at present,graphene wrapped winding microfiber composite structure is proposed and designed.As a functional material,graphene coated with winding optical fiber has excellent optical properties and can enhance temperature sensing by rapid thermal response.The surface plasmon polaron(SPP)effect produces and limits more propagation modes in the composite structure,and increases multimode interference in the structure.Therefore,the enhanced multimode interference in the experiment further improves the optical sensitivity for temperature and strain sensing.In this work,the temperature sensing sensitivity is-127.2 pm/℃,and the tensile strain sensing sensitivity is-173.9 pm/με in the experiment of the designed graphene wrapped winding micro-fiber composite structure,However,the sensing sensitivity of the winding micro-fiber composite structure without graphene is only-73.7 pm/℃ and-163.5 pm/με.In addition,the all-optical modulation of the composite structure is also studied.When the pump wavelength is 1470 nm and the power is 2.07 mW,the resonance wavelength shifts about 0.9 nm,while in the absence of graphene coating,the resonance wavelength almost does not shift.Secondly,the research status and application of the echo wall mode microcavity are analyzed at the same time,and a compact hybrid structure based on silica microsphere and single-layer graphene is proposed and designed to adjust the polarization of the optical system.This working principle is the polarization-dependent absorption of graphene and silica microsphere through the combination of the echo wall(WG)TE mode and TM mode.Moreover,Because of the difference in the field distribution and polarization of the resonance modes in the microspheres,the gap distance between the microspheres and graphene will affect the quality factor and resonance wavelength of the microspheres,and realize different changes of TE and TM WG modes respectively.The gap distance is reduced from 2.2 μm to 0.3 μm.A polarization extinction ratio of 11 dB is achieved between the resonant polarization mode in the 90°polarization direction and the resonant polarization mode in the 0° polarization direction.The former quality factor is 2.1×107,while the original quality factor of the latter is 8.3×106.This result provides an attractive and effective photon platform for the realization of high-performance polarization-selective devices.