Research On Multilayer Photonic Integrated Chips For 3D On-chip Optical Interconnection Applications

With the increasing speed of cloud computing,big data and Internet of Things information processing,electronic integrated chips have been unable to fully support such high information density and network bandwidth.Compared with electronic integrated chips,photonic integrated chips prepared by CMOS technology have attracted wide attention due to the stronger information processing capability and faster data transmission rate.However,commercial photonic chips are mainly composed of single-layer planar optical waveguide integrated circuits,which limits the expansion of optical information capacity per unit size,the expansion of channel number,and the flexibility of optical signal interaction.Therefore,multilayer photonic integrated chip has become the future development trend,which makes it attract more attention.In this paper,a multilayer photonic integrated chip for 3D on-chip optical interconnection is studied based on silicon photonic and polymer platform systems.The monolithic 2D optical phased arrays heterogeneously integrated with on-chip laser arrays based on SOI photonic platform is designed to achieve large-scale,intensive integration and energy saving solid-state lidar system applications.Based on the fluorinated polymer platform three-layer optical interconnection integrated chip,it aims to realize multi-layer stack photonic integration,expand network bandwidth and improve information processing capability by solving the problems of high absorption loss and interlayer phase dissolution in three-dimensional integration of polymer materials.The main contents of the paper are as follows:1.The monolithic 2D optical phased arrays heterogeneously integrated with on-chip laser arrays based on SOI photonic platform has been analyzed.Quantum-well laser array,electro-optical switch array,electro-optical phase shifter array,and Bragg waveguide grating antenna array are designed and optimized by Laser MOD,Lumerical and COMSOL software.In contrast to the traditional thermo-optic LIDAR chip with an external light source,the overall size of the 2D OPA chip can be limited within 1 cm~2,and the modulation rate can be increased from-μs to-ps.A large steering range is realized by tuning the phase and the wavelength of each antenna.The lasing power of each unit from the on-chip quantum well laser arrays is more than 80 m W.The operating voltages for controlling the pitch and azimuth angles are less than 1.1 and 1.0V,respectively.The overall steering range of 88.4°×18°can be achieved by tuning both the phase and the wavelength for each antenna.The proposed modulation rate of the OPA photonic chip could come to 2.5 ps.2.Triple-layered optical interconnecting integrated waveguide chip based on fluorinated epoxy cross-linking polymer photonic platform has been analyzed.The optical and thermal properties of the FSU-8 and the AF-Z-PC EP are analyzed.the vibration overtone absorption would be greatly reduced due to the C-F bond instead of C-H bond in the near infrared wavelength region.And the interlayer miscibility could be effectively inhibited by the dense epoxy cross-linked molecular network.Rsoft and COMSOL software are used to optimize the size of DC interlayer switch array,AWG-based wavelength selective switching(WSS)arrays,and MMI-cascaded channel selective switching(CSS)array.The transmission loss for the triple-layered optical waveguide chip is measured as 10.0-12.1 d B.For multilayered WSS arrays,the wavelength shifting sensitivity was about 0.48 nm/℃.For multilayered CSS arrays,the average switching time is about 280μs,and the maximum power consumption is less than 30 m W.For interlayered switching arrays,the extinction ratio is close to 15.2 d B.Based on the research of multilayer photonic integrated chips of the silicon photonic and polymer photonic platforms for the application of three-dimensional on-chip optical interconnection,the functional integration of optical devices was realized in three-dimensional space.The feasibility and application of three-dimensional photonic integrated chips was verified.