Cheng, Hao TienHao TienChengQiu, JunyiJunyiQiuPeng, Chun YenChun YenPengKuo, Hao ChungHao ChungKuoFeng, MiltonMiltonFengCHAO-HSIN WU2023-07-172023-07-172022-12-191094-4087https://scholars.lib.ntu.edu.tw/handle/123456789/633797The fabrication processes of high-speed oxide-confined single-mode (SM)-verticalcavity surface-emitting lasers (VCSELs) are complex, costly, and often held back by reliability and yield issues, which substantially set back the high-volume processing and mass commercialization of SM-VCSELs in datacom or other applications. In this article, we report the effects of Al2O3 passivation films deposited by atomic layer deposition (ALD) on the mesa sidewalls of high-speed 850-nm SM-VCSELs. The ALD-deposited film alleviates the trapping of carriers by sidewall defects and is an effective way to improve the performance of SM-VCSELs. The ALD-passivated SM-VCSELs showed statistically significant static performance improvements and reached a believed to be record-breaking SM-modulation bandwidth of 29.1 GHz. We also propose an improved microwave small-signal equivalent circuit model for SM-VCSELs that accounts for the losses attributed to the mesa sidewalls. These findings demonstrate that ALD passivation can mitigate processing-induced surface damage, enhance the performance of SM-VCSELs, and enable mass production of high-quality SM-VCSELs for mid- to long-reach optical interconnects.en[SDGs]SDG7journal article10.1364/OE.474930365586822-s2.0-85144117716https://api.elsevier.com/content/abstract/scopus_id/85144117716