Research On Design And Optimization Of Graphene-based Optical Computing Devices

The optical computing device is a new type of optical physical device,which can perform mathematical operations when the incident beams interact with the structure.Optical computing can process a large amount of data at the same time,thus it can meet the real-time information processing requirements in many fields.Therefore,optical computing devices have received extensive interest and attention.However,the current research is mainly focused on proposing a physical structure which can realize optical computing.Few studies have focused on the design and research of the flexible tunability of optical devices.In recent years,on the one hand,the use of high tunability of graphene to achieve dynamic control on optical integrated devices has become an interesting topic.On the other hand,algorithm optimization technology can be combined with graphene’s high tunability.Therefore,more flexible and better-performing optical devices can be designed.In this thesis,an optical space calculator graphene-based structure is proposed.With the advantage of the high tunability of graphene and the algorithm optimization technology,a variety of design methods are proposed,and different performance requirements are explored.The specific research work includes the following aspects:In the design and research of the optical first-order differentiator,the numerical simulation results show that when the beam waist radius of the incident beam is greater than 1.7λ,the normalized root mean square deviation(NRMSD)is less than 5%.With the optimization of genetic algorithm(GA),by adjusting the chemical potential and width of graphene,the relationship between the maximum amplitude of the differentiation result and the differentiation performance are analyzed.Moreover,the optimal design of the different differentiator for different performance requirements are studied.Compared with the initial results of GA,the numerical simulation results show that in the design of the best performance,the NRMSD is improved by 29.45%.Moreover,different weight ratios can be set to meet different requirements.The final NRMSD is improved by 22.60%under the condition of the balance of the maximum amplitude and performance parameters.In the design and research of the first-order integrator,the numerical simulation results show that the integration performance and the maximum amplitude of the integrated beam can not reach the best at the same time.The chemical potential and width of the graphene in the structure can be designed for different performance requirements.Compared with the initial results in GA,the NRMSD is improved by 25.23%in the design for the best integration performance.Compared with the existed structures,the advantage of this algorithm optimization technology is that the structure can be designed by changing different weight ratios for different performance requirements.When balancing the maximum amplitude and the performance parameters,the numerical simulation results show that the NRMSD is improved by 27.10%.In summary,this thesis designs an optical computing device based on the graphene.With the advantage of the high tunability of graphene,the structure is highly flexible and can realize optical differentiation and integration under different parameters.With the optimization of GA,the differentiators and integrators can be designed more flexibly for different performance requirements.This design and research method can promote the design and research of the more flexible and adjustable optical device.