Benefit of Rare-Earth “Smart Doping” and Material Nanostructuring for the Next Generation of Er-Doped Fibers

Abstract

Erbium-doped fiber amplifiers (EDFAs) for harsh environments require to develop specific fabrication methods of Er 3+-doped fibers (EDFs) so as to limit the impact of radiation-induced absorption. In this context, a compromise has to be found between the concentration of Erbium and the glass composition. On the one hand, high concentration of Er 3+ ions helps to reduce the length of the EDF and hence the cumulated attenuation but generally leads to luminescence quenching mechanisms that limit the performances. On the other hand, so as to avoid such quenching effect, glass modifiers like Al 3+ or P 5+ ions are used in the fabrication of commercial EDFs but are not suitable for applications in harsh environment because these glass modifiers are precursors of radiation-induced structural defects and consequently of optical losses. In this work, we investigate the concept of smart doping via material nanostructuring as a way to fabricate more efficient optical devices. This approach aims at optimizing the glass composition of the fiber core in order to use the minimal content of glass modifiers needed to reach the suited level of performances for EDFA. Er 3+-doped alumina nanoparticles (NPs), as precursor of Er 3+ ions in the preform fabrication process, were used to control the environment of rare-earth ions and their optical properties. Structural and optical characterizations of NP-doped preforms and optical fibers drawn from such preforms demonstrate the interest of this approach for small concentrations of aluminum in comparison to similar glass compositions obtained by a conventional technique.

Erbium-doped aluminophosphosilicate all-fiber laser operating at 1584 nm

“…Those elements, either by forming a solvation shell around rare earth ions -as is the case for phosphorous -or by increasing the entropy change of mixing -as is the case for aluminum -hinder the formation of clusters and prevent the emergence of detrimental pair-induced quenching [11]. However, several problems may arise from the use of such codopants, like an undesired increase of the refractive index of the core, or radiation induced attenuation [12,13].…”

On the Effect of Low Temperatures on the Maximum Output Power of a Coherent Erbium-Doped Fiber Amplifier

“…Historically, silica fibers have been used for EDFA because of their immediate compatibility (fabrication, splicing...) with the low absorption fibers used for longdistance telecommunications. Since this technological leap, many other glasses or doping methods were investigated [7], [18], [22], [29], [40], [41] to reduce the SBS gain or improve the laser amplification efficiency, but few experiments have demonstrated a positive combination on these two parameters.…”

Efficient extraction of high pulse energy from partly quenched highly Er3+-doped fiber amplifiers

“…The strengths of these types of parasitic interactions depend on the distance between the Er 3+ -ions in different ways, and at low concentrations, the separation between Er 3+ -ions can be large enough to make quenching negligible. Tailored host glasses, e.g., co-doped with Al 2 O 3 or P 2 O 5 [11,[14][15][16]49], as well as nanoparticle doping [40,41,[50][51][52][53] can also counteract quenching, but it still reappears gradually at higher concentrations.…”