Achieving Multiwavelength Optical Amplification Based on Polymer Waveguides Doped with NaYF₄:Er³⁺, Yb³⁺ Nanoparticles under Commercial and Convenient Led Pumping

Abstract Relying on a reverse energy transfer mechanism between erbium (Er³⁺) and ytterbium (Yb³⁺) ions, optical gains at wavelengths of 1550, 980, and 1067 nm are achieved in NaYF₄: Er³⁺, and Yb³⁺ nanoparticles‐doped polymer waveguides under excitation of low‐power light‐emitting diodes (LEDs) instead of 976 or 1480 nm semiconductor laser as pump sources. The optical gains at 1550, 980, and 1067 nm are demonstrated in five waveguide structures: active‐rectangular, evanescent‐field with and without an aluminium (Al) reflector, and dual‐active hybrid with and without an Al reflector. The maximum relative optical gains of 6.6, 4.0, and 3.8 dBcm⁻¹ are realized at 1550, 1067, and 980 nm, respectively, in a 5 mm long dual‐active hybrid waveguide with cross‐section of 4 × 10 µm, and a ≈100 nm‐thick Al reflector grown under the lower cladding layer under excitation of a 395 nm LED. This work proves the feasibility of using a low‐cost LED to realize multi‐wavelength amplification in a dense wavelength‐division multiplexing system and is thus valuable for the development of complex multi‐functional photonic‐integrated‐module mixed‐band optical communication systems.