Research On Silicon-Based Integrated Multi-Dimensional Multiplexing And Processing Technologies And Applications

In recent years,with the rapid development of modern information technology,data communication traffic has also shown an explosive growth,which puts forward higher requirements for data storage,interconnect communication and signal processing.Using photons as information carriers in optical communcations could take the unique advantages of high speed,large bandwidth and low latency,while silicon integrated photonics features the characteristics of high integration,low power consumption and low cost,providing a promising platform for the development of modern communication networks.Besides,photons could offer multiple physical resource dimensions such as frequency/wavelength,polarization,time,complex amplitude,and spatial structure,which could be developed into various multiplexing technologies as well as hybrid multi-dimensional multiplexing technology,providing the possibility for the further improvement of communication capacity.Therefore,the research on silicon integrated photonic chips for multi-dimensional multiplexing and processing has important strategic significance for the development of future high-speed and large-capacity communication networks.In order to solve the key technical problems in multi-dimensional multiplexing and processing,this thesis focuses on silicon integrated photonic devices and carries out a series of researches.The researches are studied from the further manipulation and utilization of single-dimensional resources to the multiplexing,coupling and signal processing of hybrid multi-dimensional resources,as well as from technological breakthroughs to system applications.The major contents are summarized as follows:(1)Theoretical and experimental studies on the silicon integrated mode manipulation and multiplexing technologies.(1)The generation of on-chip optical vortexes are studied theoretically and experimentally,the designed and fabricated silicon integrated vortex beam emitter could support the generation of dual-polarization and multi-order broadband optical vortex beams with high phase purity larger than 84%.Thus,the realization of space-division multiplexing communication compatible with wavelength and polarization dimensions could be enabled based on optical vortex beams.(2)The silicon integrated mode(de)multiplexer based on the structure of asymmetric directional coupler is theoretically studied,where the structure design with larger process tolerance is proposed,so that the practical device performance could be ensured for applications of on-chip mode-division multiplexing systems.(2)Theoretical and experimental studies on the programable optical signal processing technology.(1)A silicon integrated photonic signal processor is designed and fabricated,where hexagonal grid cells composed of tunable Mach-Zehnder interferometers are used to form a two-dimensional mesh network.Multiple signal processing functions such as optical filtering,optical delaying and optical routing could be realized,representing the characteristics of multifunctional and programable.(2)The self-configured application of the optical signal processor is demonstrated by introducing the adaptive algorithm of optical neural network,where the feedback control loop composed of power monitoring and voltage driving is used for modeling and training.The singnal processing function of optical routing and switching is experimentally demonstrated at the network node of optical fiber communication system,showing intelligent characteristic.(3)Theoretical and experimental studies on the silicon integrated multi-dimensional multiplexing and coupling technologies.(1)A silicon integrated(de)multiplexer with 4 ×32 channels is designed and fabricated with channel crosstalk less than-9 d B,by combining mode-division multiplexing and wavelength-division multiplexing,ultra-large-capacity optical interconnection links could be realized.(2)A multimode waveguide coupler is proposed and designed,which enables the direct mode coupling and conversion of multiple high-order guided modes between the few-mode fiber and silicon multimode waveguide based on the principle of mode evolution.The mode evolution efficiency is higher than 99%and the mode crosstalk is lower than-25 d B.So that the technology of mode-division multiplexing and polarization-division multiplexing could be directly applied to the fiberto-chip optical interconnection systems.(4)Theoretical and experimental studies on the silicon integrated multi-dimensional optical processing technology.(1)A silicon integrated 1 × 4 optical selective switch compatible with wavelength,mode and polarization dimensions is designed and fabricated,which could provide flexible data management for on-chip multi-dimensional optical networks.The inter-mode/-polarization crosstalk is characterized to be better than-15.6 d B while the inter-port crosstralk better than-25.4 d B.(2)A fiber-to-chip optical processing system for hybrid wavelength-,mode-and polarization-division multiplexing is experimentally demonstrated,where the signal processing function of the reconfigurable optical add-drop multiplexing is realized based on the multi-dimensional optical coupling between the few-mode fiber and the silicon-based integrated chip.The crosstalk between the system channels is measured to be less than-16 d B,and the total throughput is greater than 3 Tbit/s.Thus,the multi-dimensional multiplexed signal could be applied to the optical fiber-chip optical processing system,which greatly improves the transmission capacity.