Polymer-based S-band waveguide amplifier using NaYF₄:Yb,Tm–PMMA nanocomposite as gain medium

Optical waveguide amplifiers are essential to improve the performance of integrated communication systems. Previous research has mainly focused on C- and L-bands amplification, but there are few reports on S-band waveguide amplifiers. Here, we introduce a polymer-based waveguide amplifier that uses a NaYF₄:Yb³⁺,Tm³⁺ nanoparticles–PMMA nanocomposite as gain medium, which can provide loss compensation in the S-band. To obtain the strongest emission luminescence at 1480 nm, we optimized the doping concentration of Yb³⁺ and Tm³⁺ to 20% and 1%, respectively. By copolymerizing the nanoparticles and methyl methacrylate monomers, the nanocomposite was synthesized and used as the gain medium to fabricate S-band waveguide amplifiers. A relative gain of 5.6 dB/cm was observed at 1480 nm under the excitation of a 980-nm pump laser. To the best of our knowledge, this is the first time that S-band amplification has been observed in a polymer-based waveguide amplifier. This result is expected to extend the waveband of polymer-based waveguide amplifiers to the S-band.