Silicon-based Arrayed Waveguide Grating Router With Uniform Loss For Optical Interconnects

With the promotion of data services such as ubiquitous computing and cloud computing,data centers and high-performance computers have developed rapidly in recent years.The number of CPUs and the speed of data transmission between processors have also increased.The traditional copper-based electrical interconnection method can not meet the data transmission speed of the upcoming Tbit/s.As a result,the optical interconnection technology has become the best solution at present.Optical interconnect technology has the advantages of ultra-high throughput,massive parallelism,low access latency and low power consumption.Arrayed Waveguide Grating Router(AWGR),as the key component in the optical interconnect system,enables simultaneous interconnection between multiple links,and as a passive device,no additional control circuitry is required.On the other hand,the development of silicon photonics has made AWGR based on silicon nanowires have the advantages of high integration and low manufacturing cost.As optical interconnect systems become more and more demanding for integrated devices,heterogeneous integration technologies have evolved.Simultaneous implementation of light sources,modulators,wavelength division multiplexers and detectors on silicon-based materials is the future of integrated optoelectronics.In this paper,the research on AWGR based on silicon nanowires is carried out,and a heterogeneous integration scheme using flip chip technology is proposed.First of all,we introduce the basic working principle of arrayed waveguide grating(AWG),including key structural parameters and performance parameters.Next,the influence of structural parameters on the performance of AWG was analyzed.We also introduced the design progress of the AWG and two commonly used arrayed waveguide structures.Then the simulation method of AWG is introduced,including waveguide mode,free transmission region propagation and coupling between waveguide mode and slab mode.We present an experimental approach to realize silicon nanowire waveguide devices on a silicon-on-insulator(SOI)material platform and how to test the device.We introduced the principle and routing property of AWGR,and gave a design example of implementing silicon nanowire AWGR on SOI platform.The simulation of AWGR was carried out and the simulated spectra were obtained.Then we demonstrated the AWGR of 4×20 nm,8×6.4 nm,8×3.2 nm and 15×1.6 nm,which achieved low insertion loss and low crosstalk.Then we introduce the auxiliary waveguide method to improve the loss uniformity of AWGR.By adjusting the output light field of the array waveguide,the flat-top intensity distribution can be obtained on the image plane,thus achieving low loss nonuniformity.We optimized the auxiliary waveguide structure of 8×3.2 nm and 15x1.6 nm AWGR and demonstrated it experimentally.The channel loss non-uniformity of the fabricated AWGR is 0.5 dB.Finally,we propose a heterogeneous integration scheme based on flip-chip technology.The V-coupled cavity laser is heterogeneously integrated with the silicon nanowire AWGR by using flip-chip technology to realize the optical routing chip.We analyzed the details of the integration scheme and gave specific implementation methods.We designed,fabricated and tested discrete devices.We also introduced the flip-chip process in detail and conducted exploratory experiments.As the key component of the future optical interconnect system,silicon nanowire AWGR still needs further research and exploration.Integration with other optical devices will make it an increasingly important role in optical communications.