(INVITED) Bi-doped optical fibers and fiber amplifiers

Bismuth (Bi)-doped aluminosilicate, phosphosilicate, germanosilicate and high (⩾50 mol%) germanosilicate fibers have shown luminescence around 1.15 μm, 1.3 μm, 1.45 μm and 1.7 μm, respectively. Bi-doped fibers have paved the way for developing optical amplifiers and fiber lasers in the wavelength region of 1150–1500 nm and 1600–1700 nm, where it can serve a wide range of applications in astronomy, imaging, medicine and advanced optical communications. However, spectroscopic study is required to understand the nature of near-infrared (NIR)-emitting Bi active centers (BACs) to improve the efficiency of Bi-doped fiber amplifiers and lasers. In this paper, we review the luminescence properties of Bi-doped glasses as well as Bi-doped fibers with aluminosilicate, phosphosilicate, and germanosilicate glass hosts. Absorption and emission cross-sections of Bi-doped phosphosilicate fibers are reported. In addition, we review the current state of the art of Bi-doped fiber amplifiers development in the second telecom window (O-band) and in the E-band and S-band for the next-generation high-capacity optical communications.