Research And Optimization Of Silicon-based Photonic Passive Devices Based On Taper Waveguide

With the rapid development of information industries such as optical communications,computers,and the Internet,people have higher requirements for information capacity,speed,and cost.But the traditional electrical interconnect technology can no longer meet people's needs due to its own limitations.Therefore,the optical interconnection technology emerges as the times require,and the silicon-based on-chip optical interconnection technology has attracted more and more researchers and companies' attention due to its unique advantages.However,the integration of silicon-based photonics chips is still difficult to achieve due to many difficulties in the field of silicon-based photonics,such as the loss and size problems of silicon-based optical devices,making it difficult to achieve commercial standards.This article will focus on the research and optimization of silicon-based passive devices based on tapes.The role of the reverse taper in reducing the reflection of the silicon waveguide end-face and the position and role of the taper in optimizing the silicon-based passive device are analyzed in detail.The work of this paper has greatly promoted the reduction of the loss and size of silicon-based optical devices and is beneficial to the realization the integration of silicon-based photonics chips in the future.The specific arrangement of the paper is as follows:First of all,it describes the development and advantages of silicon-based photonics.The main structures and research advances of four kinds of silicon-based passive devices that can be optimized based on taper waveguides are given.They include silicon-based edge couplers,arrayed waveguide gratings,waveguide crossing and multimode interference couplers.Secondly,it introduces two basic theoretical knowledge that are closely related to the content of this paper.On the one hand,it is the theory,formula and pattern analysis of optical waveguide;on the other hand,the theory of FDTD algorithm is introduced,and the research background,application and basic theoretical formula of FDTD algorithm are analyzed.Then,the role of the reverse taper in reducing the silicon waveguide end-face reflection is analyzed.The 3D-FDTD simulation model and the actual experimentalmeasurement model are proposed.The main parameters affecting its reduction of end-face reflections are analyzed in detail,including the length,the tip width and shape of the taper,and the wavelength of the incident light.The analysis results show that the most important factor affecting the end-face reflection is the taper's tip width.Considering the current level of lithography,when the tip width is selected as 150nm,200nm,and 250nm,the reflection value can be reduced to-40dB(0.01%),-30dB(0.1%)and-20dB(1%)in order.In addition,the concave parabolic taper works better than the linear and convex parabolic tapers in reducing end-face reflection.The part of taper's optimization of silicon-based passive devices is based on four silicon-based optical devices:(1)Silicon-based end-face coupler SSC,we have given our own experimental measurement system.The concept of mode field area is used to explain that the concave parabolic taper can reduce the loss in the mode field conversion process.SSCs and tapers that reduce reflections on the silicon-based waveguide end-face are better for this shape;(2)Arrayed waveguide gratings,we analyzed its basic principles and main parameters,and optimized the taper of its two,connections;(3)In the aspect of waveguide crossing,we analyzed in detail its two types of taper-added structures,and presented a single-waveguide crossover simulation optimization result;(4)Multimode interference coupler,we analyzed its main parameters,and gave a simulation optimization result of 1 x2 MMI.Finally,we summarized the main work and points of this paper,and put forward some prospects for the current lack of certain work,and pointed out the direction of future research.