Research On Slow-Light Characteristics And Elecro-optic Switch Based On Microring Resonators

With the rapid development in the field of information and communication,traditional electronic communications and electrical switching can not meet people's daily needs.All-optical network will inevitably become the trend of Internet development.Microring resonators play an important role in optoelectronics.Various optical devices constructed by microring resonators,such as dense wavelength division multiplexers,optical routers and optical switches,have become the focus of the research of integrated optics.The slow-light characteristics of parallel microring resonator arrays and the electro-optic switch based on nested microring resonators are studied respectively.The phase shifter is added to the straight waveguide to realize the dynamic tuning of each slow-light channel while the speed of light in the channel is slowed down;By using the nested microring resonators structure,the switching voltage of the electro-optic switch is reduced,and the performance of the dense wavelength division multiplexing system is improved.The main work is shown as follows:(1)Based on the theory of microring resonators,side-coupled parallel channel microring resonators and vertical-coupled cross-channel microring resonators are studied,and several main parameters to measure the performance of microring resonators are discussed.Mathematical model of micro-ring resonator is established by using coupled mode theory,and the relationship between coupling coefficient and parameters of microring resonators is deduced and simulated.On the basis of coupled mode theory,the transfer matrix method is studied to deduce the relationship between the output port and the input port of the microring resonators effectively.Without loss of the microring,the optical intensity of the output port is equal to that of the input port.(2)By using transfer matrix method,the mathematical models of single microring single waveguide microring resonators and single microring double waveguide microring resonators are established.The slow-light characteristics of two kinds of microring resonators are simulated and analyzed,and the conditions of slow-light characteristics of microring resonators under different structures are obtained.When studying the slow-light characteristics of microring resonator arrays,the microring resonators arrays are decomposed into many small transmission units by using the transfer matrix method,and the spectrum functions of thet through port and download port of the microring resonator arrays are obtained.The effects of parameters such as amplitude transmission coefficient,microring refractive index,microring loss coefficient and the distance between two adjacent microrings on the output spectrum are simulated and analyzed,and the slow-light characteristics of micro-ring resonator arrays with different radius and number of micro-rings are analyzed.By using additional phase shifter,the effective phase shift of the microring resonator arrays are changed,and the dynamic tuning of each slow-light channel is realized,which enhances the flexibility of the device.(3)Aiming at the defect of high switching voltage of traditional electro-optic switch,an electro-optic switch structure of nested microring resonators is proposed.A small microring is nested in the original microring,so that there is only one coupling zone between the two microrings.The polarized polymer is used as the material of the microring waveguide core,and the external voltage is added to the small microring.According to the electro-optical modulation theory,the simulation results show that when the external voltage is very small on the microring,the requirement of the optical switch can be satisfied and the channel can be turned on and off.Then the time domain response of the device is analyzed,and the complete channel on-off time is picosecond.It is concluded that the electro-optic switch has the advantages of low switching voltage,short response time,low insertion loss and low crosstalk,which saves resources and improves the performance of the dense wavelength division multiplexing system.