Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides

Abstract

Soda-lime silicate glass has been locally doped with 0.2-at. % erbium by 3.0- and 5.0-MeV ion implantation. Single-mode fiber-compatible optical waveguides were then fabricated by use of Na+ ↔ K+ ion exchange. Characteristic photoluminescence (PL) of Er3+ centered at 1.54 μm is observed on excitation at 1.48 μm. For low pump intensity the PL decay is nearly single exponential with a lifetime of 7.2 ms. At high intensity it becomes nonexponential as a result of cooperative upconversion, an interaction between excited Er ions. Self-consistent modeling of the PL intensity and decay data yields an upconversion coefficient of 3.2 ± 0.8 × 10−24 m3/s. The effect of upconversion on optical gain is shown and discussed. An extrapolation of measured optical gain shows that 1 dB/cm of net gain is possible in the present Er-implanted soda-lime glass.