Simple Broadband Bismuth Doped Fiber Amplifier (BDFA) to Extend O-Band Transmission Reach and Capacity. - Vitaly Mikhailov; Mikhail Melkumov; Daryl Inniss; Aleksandr Khegai; Konstantin Riumkin; Sergei Firstov; Fedor Afanasiev; Man F. Yan; Yingzhi Sun; Jiawei Luo; Gabriel S. Puc; Scott D. Shenk; et al. (OFC, 2019)