基于掩埋隧道结与亚波长光栅的晶体管型VCSEL的研究

The ever-increasing demand for broadband capacity of short-reach optical communication networks, high frequency and wideband operation of microwave photonic systems puts enormous requirements on the semiconductor laser used in the optical transmitter such as the VCSELs. It has proven extremely difficult to push the modulation bandwidth of VCSELs beyond current record and radically new device concepts are demanded to meet the upcoming needs in the applications of optical communication, interconnection and microwave photonics. This project aims for the development of a novel semiconductor transmitter, which is referred to as a T-VCSEL, and will involve all elements of the development from design through fabrication to extensive device characterizations, in particular the effect of modulation bandwidth enhancement. The theoretical model of carrier dynamics will be established in accordance to the new features of a buried tunnel junction (BTJ) and a high-index-contrast subwavelength grating (HCG) incorporated as the confinement scheme and reflection mirror, respectively. Based on the device optimization study, the influences of different mesa structures, doping and intracavity contacting schemes will be evaluated. The proposed T-VCSELs will be fabricated making use of an epitaxial regrowth technology and fully characterized. It will be concluded by the implementation of this project how T-VCSELs exhibit singlemode emission with the polarization control ability and how T-VCSELs have bandwidth surpassing those of conventional diode-type VCSELs. In addition, the unique characteristics of a T-VCSEL such as three-terminal configuration offer microwave photonics applications which is not possible with a conventional VCSEL. The T-VCSELs will be explored to generate signal mixing and frequency multiplication, on the other hand, the collector output voltage can be used as a direct feedback signal (with no need for optical-to-electrical conversion) to enhance the linearity of the device. In conclusion, this project proposal deals with the design, fabrication and analysis of a GaAs-based T-VCSEL with BTJ confinement scheme and HCG reflector, a device previously not realized or investigated in great detail, in order to pave the road for various applications.

以垂直腔面发射激光器(VCSEL)为代表的传统半导体激光器存在直调带宽提升能力有限 、功能单一等关键问题，严重制约了其在下一代高速光通信、光互连以及微波光子系统中的应用。本项目以新型晶体管垂直腔面发射激光器(T-VCSEL)为研究对象，对其光电信号输出特性规律以及调制带宽增强机理进行深入的理论与实验研究。拟建立基于掩埋隧道结与亚波长光栅的GaAs基p-n-p型T-VCSEL器件的载流子动力学模型，阐明不同器件结构、工作状态和工作模式对其光电输出特性的影响；研究器件加工制作和性能表征的方法，验证理论模型对器件调制带宽增强条件的预测；研究器件的自反馈控制及其在线性微波光子链路及微波光子混频中的应用；探索在提升调制带宽的同时实现偏振态可控的高功率单模输出光特性的优化方法。本项目将有效提升T-VCSEL的调制带宽，改善其输出光特性，拓展其功能，为其在高速光通信、光互连及微波光子系统的应用奠定基础。

以垂直腔面发射激光器(VCSEL)为代表的传统半导体激光器存在直调带宽提升能力有限 、功能单一等关键问题，严重制约了其在下一代高速光通信、光互连以及微波光子系统中的应用。本项目以新型晶体管垂直腔面发射激光器(T-VCSEL)为研究对象，对其光电信号输出特性规律以及调制带宽增强机理进行深入的理论与实验研究。完成了基于掩埋隧道结与亚波长光栅的GaAs基p-n-p型T-VCSEL器件的结构设计和工艺方案开发；基于国产光芯片工艺平台成功研制了高性能直调VCSEL芯片，并通过性能测试成功验证了掩埋隧道结对于激光器芯片直调带宽的提升作用。本项目有效提升了VCSEL的调制带宽，改善其高速眼图的光特性，为高速激光器芯片的国产化和T-VCSEL的制备奠定了了基础。