Time-domain measured resonant absorption-induced change in group delay of erbium-doped silica fibers

The resonant group-delay spectra of two erbium-doped silica fibers are measured in the time domain with interferometric measurement setup in the wide-wavelength range from 1.5 to 1.6 μm. The spectrum of the absorption-induced change in dispersion of the erbium-doped silica fibers reveals resonant peaks at 1.53, 1.55, and 1.58 μm that are dependent on the Er3+ concentration and the fiber core codopants. The change can be as large as 20 ps/(nm km) at 1.535 μm. for a 250 parts-in-106 Er3+ concentration with no Al2O3 as a codopant.