Absorption cross section for the 4 I 15/2 → 4 I 13/2 transition of Er3+ in Si:Er:O/SOI epitaxial layers

Optical losses caused by the interaction of radiation with optically active Er³⁺ ions in epitaxial waveguide structures Si:Er/SOI have been directly measured. The cross section for the ⁴I_13/2 → ⁴I_15/2 radiative transition in the Er³⁺ ion has been estimated as σ_{300 K} ∼ 8 × 10^‑19 cm² at T = 300 K and σ_{10 K} ∼ 10^‑17 cm² at T = 10 K.