Clustering engineering in tellurium-doped glass fiber for broadband optical amplification

Dense wavelength division multiplexing (DWDM) is recognized as one of the leading technologies for resolving the internet data traffic capacity issue. Although the successful development of rare-earth doped fiber amplifiers enables to achieve optical signal amplification in various telecommunication wavebands, their bandwidth is limited by the inherent sharp 4f electronic transition. Here, we propose the clustering engineering strategy in tellurium (Te)-doped glass fiber for broadband optical amplification. The correlation among the glass system, chemical state of Te and the optical response are systematically studied. The active Te-doped phosphate glass with intense and broadband luminescence is successfully achieved by control of the cluster state of the Te atoms. Subsequently, Te-activated phosphate fiber is successfully drawn and the optical response is transferred smoothly. Importantly, the amplified spontaneous emission and broadband optical amplification are achieved for the first time in Te-doped glass fiber. A small signal on-off gain covering an ultra-wide range of O + E + S + C + L bands is observed under excitation at 808 nm. Our results establish a critical step toward advancing Te-based photonic materials for novel broadband fiber amplifiers serviced in telecommunication system.