The cooperative upconversion processes of erbium ions in silver film ion-exchanged waveguides in a phosphate glass were studied from the pump intensity dependence of luminescence decay curves. Cooperative upconversion coefficients of the 4I13/2 level, 7.7 ± 0.7 × 10-19 and 9.3 ± 0.7 × 10-19 cm3/s, were obtained for an Er3+ concentration of 1 × 1020 cm-3 in bulk and waveguide samples, respectively. These values are 1 order of magnitude smaller than the ones reported for silica glass. The increase in the cooperative upconversion coefficient with the increase in Er3+ concentration was found to be small. The effects of cooperative upconversion on the gain performance were analyzed for different Er3+ concentrations by a theoretical model based on experimentally measured gain with a 1.48-μm pump wavelength. Given the small cooperative upconversion coefficients in this glass, Er3+ concentrations potentially as high as 3.7 × 1020 cm-3 were shown to be feasible. Such high concentrations would result in a 12-dB gain at 150-mW pump power with a 4-cm-long waveguide.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|State||Published - Jul 1997|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics