Recently, an assistant professor Zheng Kezhi's team from the School of Physics at South China Normal University, in collaboration with Professor Wang Fei's team from Jilin University, has made a breakthrough in the research of rare-earth-doped nanocrystals-based S-band polymer optical waveguide amplifiers. The related findings have been published in Nano Letters.
Optical waveguide amplifiers are the core components of modern optical communication systems. Compared to optical fiber amplifiers, optical waveguide amplifiers have advantages such as simple manufacturing processes, small device sizes, and easy integration with other miniaturized devices on silicon wafers. In recent years, with the rapid development of integrated photonics, the research on constructing low-power and high-stability optical amplifiers using integrated optical waveguides has attracted great attention from researchers. With the doping of rare-earth nanocrystals, researchers have obtained valuable research results in the C-band polymer optical waveguide amplifiers. However, due to the low-efficiency light emission of rare-earth ions in other optical communication bands, polymer optical waveguide amplifiers operating in low-loss bands such as S and L have been rarely reported, making it difficult to meet the future bandwidth requirements of optical communication.
To address the above issues, researchers proposed introducing deactivating ions Tb3+ into NaYbF4:Tm3+ nanocrystals, utilizing energy transfer from Tm3+ to Tb3+ ions to accelerate the decay of the Tm3+ ion's 3F4 level, thereby doubling the conversion efficiency of Tm3+ ion's emission at 1464 nm (3H4→3F4). They polymerized the prepared rare-earth nanocrystals with PMMA through unsaturated double bonds on their surfaces, not only avoiding the aggregation of nanocrystals in the polymer matrix but also significantly increasing the doping concentration of rare-earth nanocrystals. By using rare-earth nanocrystal-PMMA composite material as the gain medium, they constructed an optical waveguide amplifier and achieved a relative gain of 18 dB at 1464 nm using 980 nm laser as the pump light.
This research proposes a new method to improve the down-conversion luminescence of Tm3+ ions, opening up new avenues for the development of rare-earth-doped S-band polymer optical waveguide amplifiers.
The research was supported by the National Natural Science Foundation of China, the Guangdong Provincial Outstanding Young Talent Team Project, the Guangdong Provincial Natural Science Foundation, and the Guangzhou Science and Technology Plan Project, among others.
Related paper information: https://doi.org/10.1021/acs.nanolett.3c04725
