Er3+ excited-state absorption in an erbium-doped silica fiber at the wavelengths 1490–1580 and 978 nm

The spectral features of Er3+ excited-state absorption (ESA) in an erbium-doped silica fiber (EF) at the telecom wavelengths 1490–1580 nm and at the wavelength 978 nm are reported. The measurement of the EF nonlinear transmission coefficient upon pumping the fiber in these spectral ranges, supplied with a theoretical background, allows one to obtain the spectrally dependent ESA parameter for the EF, which is defined as the ratio of the ESA to the ground-state absorption cross section.