Fundamental Research On Silicon-Based Micro-Ring Electro-Optic Modulator

As an important solution to realize large-scale integrated optical circuit,siliconbased photonics has attracted more and more attention.The modulator is also a key device in optical communication system,it plays an important role in the formation of optical communication network,its performance also affects the signal processing capability of the whole optical communication network.But there is not yet a good solution to miniaturize the modulator and to further improve the modulation rate.The electro-optical modulator based on silicon-based micro-ring resonator is not only small in size but also has high sensitivity,but the traditional micro-ring modulator based on the plasma dispersion effect can't obtain high modulation rate due to the carrier lifetime and drift rate.In this paper,a new type of electro-optical micro-ring modulator based on two-dimensional grapheme is introduced.Thank for the high carrier mobility and voltage controllable advantages,the modulator show better modulation effect both at 1550 nm and 2500 nm.In addition,we also design a silicon-based micro-ring electrooptical modulator based on Indium Tin Oxide(ITO).Finally,the experiment proves the modulation performance of graphene.The main research contents are summarized as follows:1.According to the electromagnetic theory,the boundary conditions are calculated and deduced,and the waveguide theory is also deduced.The theory of waveguide coupling is analyzed,which is very important for the coupling between the straight waveguide and the ring waveguide of the micro-ring resonator.Finally,the transfer matrix method was used to analyze the basic principle and properties of micro-ring resonator,and analyze the performance evaluation of micro-ring resonator.2.The silicon-based micro-ring electro-optical modulator based on graphene is designed and analyzed,and the simulation is optimized by software.The required ridge waveguide is designed.The difference between the different isolation layers is discussed.The electrical tuning performance of the embedded graphene waveguide is qualitatively analyzed.The 1550 nm micro-ring modulator with the extinction ratio of 16.77 dB and the optical bandwidth of 208.14 GHz is realized.In addition,We also design the midinfrared micro-ring modulator based on the sulfur-based glass waveguide,and realizes the mid-infrared band micro-ring modulator with extinction ratio of 33.57 d B and optical bandwidth of 133 GHz.In this paper,the electrical tuning performance of ITO is analyzed theoretically.The silicon-based micro-ring modulator based on ITO is designed.The results show that the micro-ring based on ITO can also achieve electro-optical modulation,and the modulator based on ITO with extinction ratio of 15.15 dB and optical bandwidth of 195 GHz is realized.3.The D-type fiber-optic modulator based on graphene is designed,and the electrical tuning performance of graphene is proved by simple and low-cost method.The results show that the change of the applied electric field of the graphene can realize the modulation of the optical signal.Through the above research,the feasibility of silicon-based micro-ring modulator based on graphene or ITO is proved.And the modulator also has very good modulation performance.It is of great significance in the field of optical communication systems,especially modulator.