Improved Fluorescence and Gain Characteristics of Er-Doped Optical Fiber with PbS Nanomaterials Co-Doping

Abstract

Er-doped optical fiber (EDF) with ultra-broad gain bandwidth is urgently needed given the rapid advancement of optical communication. However, the weak crystal field of the host silica glass severely restricts the bandwidth of traditional EDF at 1.5 μm. In this study, we theoretically explored the introduction of PbS nanomaterials in the silica network assisted with the non-bridging oxygen. This can significantly increase the crystal field strength of Er3+ ions in the local structure, leading to their energy level splitting and expanding the fluorescence bandwidth. Additionally, the PbS/Er co-doped optical fiber (PEDF) with improved fluorescence and gain characteristics was fabricated using modified chemical vapor deposition combined with the atomic layer deposition technique. The presence of PbS nanomaterials in the fiber core region, which had an average size of 4 nm, causes the 4I13/2 energy level of Er3+ ions to divide, increasing the fluorescence bandwidth from 32 to 39 nm. Notably, the gain bandwidth of PEDF greater than 20 dB increased by approximately 12 nm compared to that of EDF. The obtained PEDF would play an important role in the optical fiber amplifier and laser applications.

Enhanced Gain Characteristics of PbS-Doped Silica Fiber in O-Band by Co-Doping Er Ions

“…Pb(tmhd) 2 (tmhd: 22,66-tetramethyl-35-heptanedionato), H 2 S gas (10% H 2 S/N 2 mixture), Er(tmhd) 3 , Al(CH 3 ) 3 , and O 3 gas were used as reaction precursor materials for Pb, S, Er, Al, and O, respectively. The ALD process was reported in detail in literatures [14], [17], [18]. In addition, the deposited Al 2 O 3 materials can serve as protective layers and reduce the volatilization of PbS to some extent, owing to the higher melting point and boiling point than PbS materials [19], [20].…”

“…Wang et al prepared PbS and Tm 3+ co-doped glass fiber and achieved ultra-broadband luminescence at 1400-2600 nm [13]. Pan et al discovered that co-doping Er 3+ ions can enhance the local crystal field intensity and affect the local structure of the silica matrix based on theoretical studies [14]. However, the influences on the spectral characteristics near 1.3 μm was not considered in their work.…”