用于光互联高速垂直腔面发射激光器相干耦合阵列研究

The project aims at the research of key technologies and scientific questions in high speed coherently coupled vertical cavity surface emitting laser arrays for optical interconnections. Optical coupling among array elements is proposed to enhance the device modulation response. Single mode and high output power are also obtained in these coherent arrays. Thus, this method can solve the restrict between transmission data rate and distance. The research is based on the inherent relation among quantum structure, coherent coupling mechanism and array dynamic performance, to get an array structure which can achieve high frequency modulation. Photonic crystal combined with ion implant is used to design stably coherently coupled VCSEL arrays with low threshold, single mode and high output power. Novel separate contacts are employed to make current inject into every element separately. Bottom emitted structure is employed to increase heat dissipation. The key techniques of fabrication and epitaxial growth are investigated. A modal including the electronic, optical and thermal effects are established. Considering array mode, modulation rate, output power, heat dissipation and cost, optimize the array and element structures. This project is to get coherently coupled VCSEL arrays with the ability of both high speed and long transmission distance. The research results obtained by the project will provide new approaches and techniques to develop VCSELs operating with high-speed property and good performance for meeting the application requirements of the optical interconnection.

本项目对用于光互联的高速垂直腔面发射激光器(VCSEL)相干耦合阵列的关键科学技术问题进行研究。 提出利用VCSEL阵列内单元间光耦合方法提高器件的调制响应，获得单模高功率输出，克服传统VCSEL在传输速率和传输距离方面的相互制约。从单元量子结构、耦合方式与阵列动态性能的内在联系和规律入手，探索能够实现高速调制的阵列结构。采用光子晶体结合质子注入，设计出低阈值、单模高功率、稳定相干耦合的阵列；采用新型分离式电极、倒装底发射技术实现电流独立注入，实现单元相位的控制，改善散热。研究阵列制备和外延生长的关键技术。分析包括电、光、热等多物理场复杂体系，建立模型。在阵列模式、调制速率、输出功率、散热及工艺成本等互制约因素中取得对单元和阵列结构的优化。使VCSEL耦合阵列同时具有高速和远距离的数据传输的能力。为发展我国具有自主知识产权的高性能高速VCSEL器件提供新思路和新技术，满足未来光互连的需求。

高性能高速VCSEL器件在高速光互连中有着重要的应用价值，本项目针对下一代光互连技术对VCSEL的新需求，利用VCSEL阵列内单元间光耦合方法提高器件的调制响应，获得单模高功率输出，克服传统VCSEL在调制特性方面的限制。本项目研究了具有高调制带宽、高光束质量、窄光谱线宽的VCSEL耦合阵列器件。从单元量子结构、耦合方式与阵列动态性能的内在联系和规律入手，建立了耦合VCSEL阵列的理论模型，探索出实现耦合阵列的结构方法。采用质子注入结合相位修改器，设计出低阈值、单模高功率、小发散角、具有稳定模式的VCSEL耦合阵列器件；采用新型分离式电极实现电流独立注入，实现单元相位的控制，同时可实现光束的可操控偏转；采用应变量子阱、优化增益谱峰值波长与腔模的失谐值，优化器件散热结构，改善了VCSEL器件的热特性，使其能够实现高温工作。针对VCSEL耦合阵列的关键性能进行了理论与实验上的探究，如高光束质量、高温工作、高输出功率及高调制速率等，得到了器件结构的优化的方法。.成功研制出高速VCSEL相干耦合阵列，实现最大调制带宽30GHz 以上，输出功率大于10mW，光谱线宽小于0.06nm，发散角小于1.42o。以上研究可为发展我国具有自主知识产权的高性能高速VCSEL器件提供新思路和新技术，满足未来光互连的需求。