具有單模 (SM) 輸出和強抗光反饋能力的高速垂直腔面發射雷射 (VCSEL) 在進一步提高現代 AI 橫向擴展和縱向網路的共封裝光學 (CPO) 系統的封裝密度方面發揮著至關重要的作用。與傳統銅纜與數位訊號處理 (DSP) IC 的組合相比，基於 VCSEL 的光學解決方案可以大幅節省能耗並提供更高的單位面積資料速率。在本文中，我們證明，透過優化內部具有環形 Zn 擴散孔徑的 VCSEL 腔體結構，我們可以同時提高 850 nm 和 1060 nm VCSEL 的 SM 輸出功率和速度。與參考 850 nm VCSEL 相比，1060 nm VCSEL 表現出優異的 SM 特性、更高的電光 (E-O) 頻寬（22 vs. 26 GHz）以及動態操作下的小空間燒孔效應。透過將我們新穎的 850 nm SM VCSEL 與 1 公里長的漸變折射率單模光纖（在 850 nm 窗口為雙模）相結合，我們能夠顯著提升直接調變頻寬（從 22 GHz 提升至 39 GHz），透過光纖尖端的單透鏡，SM VCSEL 輸出與 SMF-28 Ultra 光纖之間的光耦合效率高達 60.5%。在 4 mA 低偏壓電流下，無需使用任何高功耗的重定時 DSP IC，即可在 1 公里光纖上實現 56 Gbit/s 的無錯誤傳輸。;High-speed vertical-cavity surface-emitting lasers (VCSELs) with single-mode (SM) output and strong immunity to optical feedback play a vital role in further improving the package density in co-packaged optics (CPO) systems for modern AI scale out and up networks. Compared with the combination of traditional copper cable with digital signal processing (DSP) ICs, the VCSEL based optical solutions can greatly save the energy consumption and provide a much larger data rate per unit area. In this thesis, we demonstrate that by optimizing the structure of VCSEL cavities with ring-shape Zn-diffusion apertures inside, we can simultaneously improve the SM output power and speed of both 850 and 1064 nm VCSELs. Compared with the reference 850 nm VCSEL, the 1060 nm one exhibits superior SM characteristic, higher electrical-to-optical (E-O) bandwidth (22 vs. 26 GHz), and much less spatial hole burning effect under dynamic operations. By combining our novel 850 nm SM VCSEL with a 1 km length graded-index single-mode fiber, which is two-mode at 850 nm window, we can obtain a significant direct modulation bandwidth enhancement (22 to 39 GHz), with an optical coupling efficiency as high as 60.5 %, between the SM VCSEL output and a SMF-28 Ultra fiber through a single lens on the fiber tip. Error-free 56 Gbit/s transmissions over a 1 km of such fiber under a low bias current of 4 mA is obtained without using any power-hungry retiming DSP ICs.
