Research On Erbium-doped Oxide Gain Materials For Optical Waveguide Amplifier

With the rapid development of emerging technologies such as 5G,artificial intelligence,cloud computing,and the Internet of Things,global data is growing exponentially,which puts forward higher requirements for information transmission rate and bandwidth.Silicon photonics technology has the characteristics of ultra-large-scale integration and ultra-high-precision manufacturing of CMOS technology,and the advantages of ultra-high speed and ultra-low power consumption of photonic technology.It is considered to be a disruptive technology to deal with the failure of Moore’s Law.However,since silicon is an indirect bandgap semiconductor with extremely low luminous efficiency,the realization of monolithically integrated on-chip light sources and active functions such as optical amplification faces great challenges.In view of the successful cases of erbium-doped fiber amplifiers（EDFA）in the communication band,erbium-doped waveguide amplifiers（EDWA）are considered to be one of the most direct and effective solutions for on-chip light sources and on-chip optical amplification.However,unlike EDFA,EDWA cannot compensate for the low unit gain through length due to its small geometric size,which requires the host material to have a high erbium doping concentration.However,not all materials have high rare-earth solubility,and High-concentration doping will cause concentration quenching phenomena such as energy cooperative up-conversion and cross-relaxation.Therefore,the research and development of new EDWA host materials has become the key to limit the further development and application of silicon-based photonics technology.Aiming at these problems,this paper firstly conducts in-depth research on the gain materials of optical waveguide amplifier with high concentration erbium doping and high gain characteristics,and successfully prepared a series of amorphous high concentration erbium doped La₂O₃-Ga₂O₃ by using aerodynamic levitation technique.Research shows that this material has strong luminescent properties in the communication band（C band）,and has good mechanical properties and thermal stability,and is an excellent EDWA host material.However,the optimal Er doping concentration of this material is 3.01×10²⁰ions/cm³.In order to further improve the solubility of erbium in the material,we replaced Ga₂O₃ with Al₂O₃,and prepared a high-concentration Er-doped La₂O₃-Al₂O₃ material.The optimal erbium doping concentration is increased to 1.6×10²¹ ions/cm³,and its stimulated emission cross section at 1535 nm can reach 4.49×10^-21 cm²,and the radiation lifetime is as high as 5.23 ms,which means that the material is an ideal EDWA host.material.In order to further verify the possibility of this material as a host material for EDWA,we established a complete theoretical gain model of waveguide amplifier,and used COMSOL Multiphysics and MATLAB to design and optimize passive s ilicon nitride and Er₂O₃-La₂O₃-Al₂O₃ mixed ridges waveguide amplifier.The optical waveguide amplifier was obtained,and its gain characteristics were simulated and calculated.The results show that the net gain of the waveguide amplifier can reach 12.13 d B/cm.This study will provide new ideas and directions for the research and development of on-chip EDWA host materials.