Work

32 dB modal gain in Er:LiNbO3 waveguide amplifiers with Er,Yb:Al2O3 cladding layer via bidirectional pumping scheme

Year: 2025

Type: article

Abstract: Lithium niobate on insulator (LNOI) holds substantial promise for applications in integrated photonic systems. Waveguide amplifiers are fundamental photonic components within integrated photonic platforms. In this paper, we report a high-gain erbium-doped lithium niobate (Er:LiNbO3) waveguide amplifier coated with an erbium and ytterbium co-doped aluminum oxide (Er,Yb:Al2O3) cladding layer. The ridge waveguide dimensions and cladding thickness were optimized via finite element method (FEM) simulations of electric field distributions, with further analysis of the impacts of optical confinement factor (Γ) and effective mode area (A eff ) on device performance. This paper further validates the advantages of a bidirectional pumping scheme in suppressing amplified spontaneous emission (ASE) and reducing noise figures (NF). Numerical simulations based on an Er3+-Yb3+ co-doped theoretical model demonstrate that under an Er3+ concentration of 3×1020 cm−3, Yb3+ concentration of 2.7×1021 cm−3, and a signal power of −30 dBm, the amplifier achieves a modal gain of 32 dB. This work establishes a theoretical foundation for the monolithic integration of compact Er3+-Yb3+ co-doped waveguide amplifiers on the LNOI platform through systematic optimization of waveguide dimensions and doping ratios.

Source: Optics Continuum

DOI: 10.1364/optcon.560648