Yang, Yun ChengYun ChengYangChen, Wei HsinWei HsinChenChiu, Chih ChuanChih ChuanChiuCHAO-HSIN WU2024-05-062024-05-062024-04-1501469592https://scholars.lib.ntu.edu.tw/handle/123456789/642300This article presents an all-epitaxy approach to reduce the root mean square spectral width (∆λR M S) of 850 nm oxide-confined vertical cavity surface-emitting lasers (VCSELs) with a large aperture of 7 µm through strategic optimization of the oxide guiding layer within the epitaxy structure. At 75°C, the VCSEL demonstrates a ∆λR M S of ∼0.3 nm at a bias current of 7.5 mA. Furthermore, the VCSEL achieves successful transmission of 26.5625 Gbaud PAM-4 modulation over a short-reach (SR) OM4 fiber link while maintaining a TDECQ budget below the 4.5 dB specified by 50G IEEE Ethernet standards.enother10.1364/OL.521023386210802-s2.0-85190506287https://api.elsevier.com/content/abstract/scopus_id/85190506287