Simple experiments are used to determine ion-pairs percentage and macroscopic homogeneous upconversion in highly erbium-doped fibers. Using these parameters in a Giles-based model enable to predict Optical-Power-Conversion-Efficiency of WDM-EDFAs with a fair agreement.

WDM amplification tests performed on highly erbium-doped fibers show that 36-dB/m fibers offer the best tradeoff to design efficient compact WDM amplifiers.

A dispersion-balanced fiber exhibiting a low chromatic dispersion slope (<0.015 ps/nm2/km at 1550 nm) was obtained by longitudinally changing the radial dimension of a refractive index profile. We report theoretical and experimental results and trade-offs between effective-area and cable ability aspects.

A Raman fiber laser emitting six output wavelengths ranging from 1415 nm to 1480 nm has been implemented. Thanks to its adaptability, it allows to manage the Raman gain and is an alternative to complex semiconductor pump modules

An EDFA covering the full C-band has been operated with a record output power of +33 dBm, owing to a new 50-mum pump design incorporating 100-mum diodes

Using high resolution laser spectroscopy, we studied the broadening of the 1.5µm transition in different glassy hosts. The distribution of erbium in the matrix is investigated and the gain spectral hole burning comportment is discussed.

The impact of attenuation spectrum and effective area of link fiber has been experimentally and numerically assessed regarding the required pump power and effective noise figure for the S-band compared to C-band and XL-bands. Compared to the C-band and XL-band, it is shown that 15% more pump power is required in the S-band compared to the C-band while 1 dB more is observed for the effective noise figure compared to the C-band. The XL-band offers better a noise figure (2 dB lower than in the S-band) with similar power performance. Indeed, the increase of effective area and decrease of material Raman coefficient with wavelength reduces the benefit brought by a lower attenuation coefficient. However, attenuation at the pump wavelength is paramount for the determination of the best noise figure. Installed fiber characteristics, particularly concerning possible bending loss in the XL-band, will finally determine the best suited solution.

A first experimental demonstration of benefit brought by photonic crystal fibers in amplification applications is reported with an air-clad ring-doping wideband cladding-pumped EDFA.