Research On SOI/Polymer Grating Interlayer Coupler With Loss Compensation

With the continuous advancement of social informatization,modern comm-unication services such as big data,cloud services and mobile applications drive the rapid development of optical communication technology.The emergence of data centers and high-performance computers also puts forward higher requirements for communication capacity.Silicon-based photonics has gradually become a key research direction of integrated optics due to its small size,compatibility with traditional semiconductor processes,and high bandwidth.It has important research significance and broad development prospects in data centers and high-performance computers.With the rapid development of silicon-based photonic chips,two-dimensional integrated silicon-based photonic chips has reached a bottleneck of integration level.To meet higher communication capacity requirements,it is necessary to integrate planar optical circuits into three dimensions.By arranging different functional photonic devices in different layers,Three-dimensional integrated optical circuits can achieve high-density,multi-functional integration under limited wafer size.The interlayer coupler proposed in this paper can realize the optical interconnection between silicon layer and polymer layer,and expand the capacity and function of silicon-based integrated optical circuits.The gain material is introduced into the polymer layer to realize the compensation of the interlayer coupling loss.The main work of this paper is as follows:1.In this paper,a reverse-pumped optical waveguide amplifier based on Na YF₄:Er³⁺,Yb³⁺nanocrystals was designed and fabricated based on the Er³⁺-Yb³⁺co-doping level system.The Na YF₄:Er³⁺,Yb³⁺nanocrystals with oleic acid coating on the surface were synthesized by high temperature thermal decomposition method,and the morphology and spectral characteristics of the nanocrystals were characterized.Nanocrystals are dispersed in polymer photoresist as gain medium,and polymer photoresist is used as waveguide core material after mixing uniformly,and a polymer optical waveguide amplifier is prepared by wet etching process.A reverse pump horizontal coupling test platform was built to test the gain performance of the polymer optical waveguide amplifier.A relative gain of 9.4 d B was measured at 1530 nm under the excitation of the980 nm reverse pump light.2.The grating coupler used for silicon-based photonic chip coupling is studied,and the principles of grating coupler and finite difference time domain method are expounded.The key parameters such as the period and duty cycle of the silicon-based grating coupler are scanned and optimized by the FDTD algorithm.After the simulation design,coupling efficiency of the uniform grating coupler with a coupling is 61.51%,3-d B bandwidth of the uniform grating coupler is 70.5 nm.3.Based on the research of optical waveguide amplifier and grating coupler,a silicon/polymer interlayer coupler with loss compensation function is proposed in this paper.The designed device structure can compensate the interlayer loss by passing reverse pump light through the polymer layer.The FDTD algorithm is used to scan and optimize the parameters,such as the grating period and the position of the gold mirror.Finally,the interlayer coupler with a coupling efficiency of 58.88%is obtained,When the input signal light is 1 m W,the loss compensation performance of 7.26 d B is obtained by simulation calculation,and the output signal after loss compensation is 3.09 m W.This research realizes the three-dimensional optical integration of silicon and polymer integrated optical circuits,which has theoretical significance for the study of silicon/polymer hybrid integrated optical circuits.The designed interlayer coupler can also realize the high-efficiency coupling of the silicon photonic chip,which provides a solution for the packaging of the silicon photonic chip.