{"title":"80 Gbps PAM-4 Data Transmission With 940 nm VCSELs Grown on a 330 μm Ge Substrate","authors":"Yun-Cheng Yang;Zeyu Wan;Chih-Chuan Chiu;I-Chi Liu;Guangrui Xia;Chao-Hsin Wu","doi":"10.1109/LED.2024.3462949","DOIUrl":null,"url":null,"abstract":"940 nm oxide-confined vertical-cavity surface-emitting lasers (VCSELs) on \n<inline-formula> <tex-math>$330~\\mu $ </tex-math></inline-formula>\n m thick Ge bulk substrates were fabricated and characterized, presenting a novel approach to VCSEL manufacturing. The wafer surfaces demonstrated high smoothness and flatness, with a peak-to-valley wafer distortion of \n<inline-formula> <tex-math>$50.3~\\mu $ </tex-math></inline-formula>\n m, a root mean square roughness (Rq) of 1.34 nm, and an average wafer bow-warp of \n<inline-formula> <tex-math>$3.77~\\mu $ </tex-math></inline-formula>\n m. The Fabry-Pérot dip precisely aligned with the target wavelength, while stopband center mapping exhibited excellent uniformity across the wafer, with a 1.937 nm (0.206%) standard deviation. At 300 K, the Ge-based VCSEL with a \n<inline-formula> <tex-math>$6~\\mu $ </tex-math></inline-formula>\n m oxide aperture achieved an optical peak power of 5.5 mW and a maximum modulation bandwidth of 19.8 GHz, with a roll-over current surpassing 16 mA. Furthermore, the device demonstrated successful data transmission at 53.125 Gbps and 80 Gbps using PAM-4 modulation, achieving transmitter and dispersion eye closure quaternary (TDECQ) penalties of 1.36 dB and 4.70 dB, respectively. These results underscore the potential of thin Ge substrates in advancing VCSEL technology for high-speed optical communication applications.","PeriodicalId":13198,"journal":{"name":"IEEE Electron Device Letters","volume":"45 11","pages":"2070-2073"},"PeriodicalIF":4.1000,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Electron Device Letters","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/10683733/","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
引用次数: 0
Abstract
940 nm oxide-confined vertical-cavity surface-emitting lasers (VCSELs) on
$330~\mu $
m thick Ge bulk substrates were fabricated and characterized, presenting a novel approach to VCSEL manufacturing. The wafer surfaces demonstrated high smoothness and flatness, with a peak-to-valley wafer distortion of
$50.3~\mu $
m, a root mean square roughness (Rq) of 1.34 nm, and an average wafer bow-warp of
$3.77~\mu $
m. The Fabry-Pérot dip precisely aligned with the target wavelength, while stopband center mapping exhibited excellent uniformity across the wafer, with a 1.937 nm (0.206%) standard deviation. At 300 K, the Ge-based VCSEL with a
$6~\mu $
m oxide aperture achieved an optical peak power of 5.5 mW and a maximum modulation bandwidth of 19.8 GHz, with a roll-over current surpassing 16 mA. Furthermore, the device demonstrated successful data transmission at 53.125 Gbps and 80 Gbps using PAM-4 modulation, achieving transmitter and dispersion eye closure quaternary (TDECQ) penalties of 1.36 dB and 4.70 dB, respectively. These results underscore the potential of thin Ge substrates in advancing VCSEL technology for high-speed optical communication applications.
期刊介绍:
IEEE Electron Device Letters publishes original and significant contributions relating to the theory, modeling, design, performance and reliability of electron and ion integrated circuit devices and interconnects, involving insulators, metals, organic materials, micro-plasmas, semiconductors, quantum-effect structures, vacuum devices, and emerging materials with applications in bioelectronics, biomedical electronics, computation, communications, displays, microelectromechanics, imaging, micro-actuators, nanoelectronics, optoelectronics, photovoltaics, power ICs and micro-sensors.