Synthesis and study of novel erbium-doped La2O3-Al2O3 glasses for on-chip waveguide amplifier

Highlights: • The optimal Er³⁺ doping concentration is up to ~1.61 × 10²¹ cm⁻³. • The luminescence lifetime in the communication waveguide is up to 5.23 ms. • The refractive index of glass is as high as ~1.97, which is higher than that of Al₂O₃ (n = 1.65). • An internal net gain of up to 12.13 dB/cm is predicted at C-band from a simple hybrid waveguide amplifier designed with Si₃N₄ and 5Er₂O₃-44La₂O₃-51Al₂O₃. -- Abstract: Highly erbium-doped xEr₂O₃-44La₂O₃-(56-x)Al₂O₃ glasses are synthesized by an aerodynamic levitation (ADL) technique. The optimum erbium-doped concentration in 5Er₂O₃-44La₂O₃-51Al₂O₃ glass can reach ~1.61 × 10²¹ cm⁻³. All the fluorescence emission spectra of the glasses under different wavelength bands are measured. The results show the strongest emission intensity at communication band (C-band). The longest radiation lifetime in ⁴I_13/2 → ⁴I_15/2 transition is about ~5.23 ms. The Judd-Ofelt (J-O) parameters of 5Er₂O₃-44La₂O₃-51Al₂O₃ glass are also calculated to evaluate the potential of the glass as a substrate material for optical waveguide amplifier. Based on the parameters of the glass, We used MATLAB to write the gain simulation model of the waveguide amplifier, combined with the COMSOL software to simulate and optimize the waveguide geometry, and calculated the overall gain characteristic curves of optical waveguide amplifiers with different lengths are calculated theoretically. An internal net gain of up to 12.13 dB/cm in the C-band is obtained from the hybrid waveguide amplifier with 1 cm.