Study On Silicon Photonic Microring Based Modulation And Multiplexing Devices

Silicon photonics has developed rapidly in the past few decades.Various silicon photonic devices have emerged continuously,which leads to an industrial scale.Improving the channel capacity of optical communication system becomes an inevitable requirement of modern data transmission.On this basis,multiplexing technology arises at the historic moment.Wavelength division multiplexing（WDM）is the common-use multiplexing technology,which has been developing rapidly in the past thirty years.From the initial application of optical fiber to the present integrated WDM system,the trend of miniaturization,integration and low energy consumption is becoming more obvious.Modulators are often used in WDM systems.The common modulator structures are Mach-Zehnder interferometer modulator（MZM）and microring resonator modulator（MRM）.Although Mach-Zehnder interferometer modulator is not sensitive to temperature and has a large bandwidth,its shortcomings of large chip area and high power consumption are more prominent,which does not conform to the trend of WDM system miniaturization and low energy consumption.At the same modulation efficiency,the microring modulator can achieve higher integration and lower energy consumption,so the research of microring modulator becomes an important part in WDM system.Moreover,with the further increase of data volume in daily life,WDM system is difficult to meet the requirements of high-throughput data transmission,and it has many disadvantages in the future information society.The combination of wavelength division multiplexing and modulus division multiplexing can significantly improve the amount of coding.It can effectively improve the ability of information transmission.In order to realize high-speed WDM system,a high-speed microring modulator at transmitter is studied.In addition,in order to further increase the information transmission flux and meet the requirements of the miniaturization of multiplexing system,WDM and MDM technology of a single device is explored at the receiving end.The main work contents are as follows:1)Microring modulator design and equivalent electric circuit modelA high modulation rate microring modulator is designed.An appropriate MRM is designed according to the WDM system.The modulation rate,modulation efficiency,free spectral range,3d B optical bandwidth and other parameters of the microring modulator are reversely obtained by the design of total bandwidth,channel spacing and system modulation rate of the WDM system.The reasonable structure of microring resonator and PN junction for modulation are designed according to the parameters above.At last,the MRM is tested experimentally.The optical response of the microring modulator is expressed as extinction ratio of-9.4 d B,optical bandwidth of 18.7 GHz and modulation efficiency of 1.418 V·cm.The tuning efficiency is better and device size is smaller than MZM.The behavior model of microring modulator is studied from the view of equivalent circuit.Due to the influence of electric elements on the fabrication of the microring modulator,the response speed and size of the microring modulator cannot reach the extreme.The co-design,processing,testing and packaging of electronic and photonic devices on silicon platform is gradually gaining popularity.The co-design scheme can effectively reduce the noise of the microring modulator,improve the response rate,improve the communication capacity and fidelity and reduce the size of the microring.Thus,studying the behavior model of optical devices in CMOS platform become significant.In the thesis,the behavior model of microring modulator is studied from the perspective of equivalent circuit.The dynamic model parameters are obtained by extracting the response of the microring modulator.The simulated resonant wavelength of the microring modulator is 1552.6 nm with modulation efficiency of 1.433 V·cm,the optical response can be expressed as extinction ratio of-9.2 d B and optical bandwidth is 16.2 GHz.2)Hybrid wavelength-and mode-division multiplexing system based on microring resonators with mode splitterA wavelength-and mode-hybrid multiplexing microring resonator is proposed in the thesis.As the volume of data explodes,the amount of information that WDM systems can carry is increasingly limited.Apart from wavelength division multiplexing,polarization division multiplexing（PDM）,mode division multiplexing（MDM）,the combination of different multiplexing technologies will highly improve the competence of transferring information.The hybrid multiplexing combining MDM and WDM is such a multiplexing technology that can greatly enhance the information carrying capacity.At present,WDM-MDM hybrid multiplexing technology mostly adopts cascading different MDM functional devices,which leads to the oversized system,the low level of integration and power consumption.Besides,it is difficult to use a single microring structure to achieve WDM-MDM hybrid multiplexing.In the thesis,a new structure of microring resonator is proposed.The single microring resonator can realize WDM-MDM hybrid multiplexing.In the coupling region of the drop port of the microring resonator,a mode splitter based on a slot waveguide is used to split the TE₀and TE₁ modes.This ring also has the capacity to select wavelength.The simulation results show that the microring resonator has the ability to split TE₀ and TE₁ modes.The optical bandwidth of MRR at 1550 nm is 52 GHz,the insertion loss is better than0.66 d B and the allowable manufacturing error range is-10 nm to+15 nm.The demonstrated wavelength-mode hybrid multiplexing system can effectively split TE₀and TE₁ modes of different wavelengths,and the total insertion loss of the multiplexing system is better than 2.3d B.