基于PAM4制的高速垂直腔面发射激光器研究进展

短距离光互联技术在云计算、5G通信、物联网技术等方面有重要的商业应用价值。基于高速垂直腔面发射激光器(Vertical-cavity surface-emitting laser,VCSEL)与多模光纤组成链路、采用直接调制检测、并使用如四电平脉冲幅度调制(Four-level pulse amplitude modulation,PAM4)等的高阶调制模式是现阶段短距离光互联链路方案的首选。本文首先介绍了短距离光互联应用的研究现状;第二部分介绍了VCSEL的发展、结构以及动态参数;第三部分介绍了PAM4调制方法及伴随使用的各种电子技术(均衡,前向纠错,脉冲整形);第四部分介绍了提高单链路速率的波分复用(Wavelength division multiplexing,WDM)技术;最后对以高速VCSEL、多模光纤、直接调制检测、PAM4调制以及波分复用技术的短距离光互联方案应用前景做了总结和展望。

High-speed Vertical-cavity Surface-emitting Lasers Based on PAM4 Modulation

The short-reach optical interconnection technology has important commercial application value in many fields,such as cloud computing,5G communication and internet of things technology.The system based on high-speed vertical-cavity surface-emitting lasers(VCSELs)and multi-mode fiber,using direct modulation detection and high-order intensity modulation mode such as four-level pulse amplitude modulation(PAM4)is proved to be an ideal solution for short-reach optical interconnection.In this article,firstly,the research of short-reach optical interconnection is introduced;secondly,the development,structure and dynamic parameters of VCSELs are studied;thirdly,PAM4 modulation method and various electronic technologies(equalization,forward error correction and pulse shaping)are reviewed;fourthly,the wavelength division multiplexing(WDM)technology which can increase the rate of single link is mentioned;lastly,summary and outlook of the short-reach optical interconnection technology based on high-speed VCSEL,multimode fiber,direct modulation detection,PAM4 modulation and WDM are introduced.