Research On Mechanism And Technology Of Electro-optic Modulation Of Transitional Metal Dichalcogenides

The fifth-generation mobile communication technology puts forward rigorous requirements such as high bandwidth,high integration,low energy consumption and low cost on electro-optic modulator,which is the key device of optical communication and interconnects.Since conventional electro-optic modulators cannot meet these requirements at the same time,it is urgent to build high-performance electro-optic modulators based on new functional materials.Transitional metal dichalcogenides(TMDCs),as a group of twodimensional semiconductors,have the potential to build high-performance electro-optic modulators due to their various electro-optic response,high theoretical mobility and easy integration.However,the electro-optic modulation mechanism of them in the non-resonant region is still unclear,and a theoretical model able to describe their electro-refractive response and electro-absorptive response in both resonant and non-resonant regions is absent,which have severely limited the progress of the research on TMDC modulators.Based on k·p method and first principle calculations,the paper firstly construct the band model and analyze the band characteristics.Combining the band model and Kubo formula,an electro-optic response model of TMDC s is then established by introducing the assumption of simplifying the transitions and neglecting the phonon effect.Based on the electro-optic response model,this paper demonstrates the electro-optic response characteristics and explains the process with molybdenum disulfide(M0S2)as an example.Afterwards,the electro-optic response curves of six VIB group TMDCs are calculated and their characteristics are discussed.This paper verifies the validity of the model by comparing the theoretical and experimental results.Subsequently,this paper designs a TMDC phase modulator operating in C-band,analyzes the performances with finite element method and equivalent circuit model and compares it with graphene phase modulator.It turns out that TMDC phase modulators possess excellent modulation efficiency and low insertion loss.The paper also proposes a scheme to improve the modulation speed of TMDC modulators.Finally,the whole paper is summarized,giving the idea of further modeling of the electro-optic characteristics of TMDCs and looking into the future of TMDC high-performance modulators.