# The Interplay Between Radiation-induced Attenuation, Photodarkening and Photobleaching at Pump Wavelength in Er-and Yb-doped Silica Optical Fibers

Franck Mady, Mourad Benabdesselam, Wilfried Blanc

► To cite this version:

Franck Mady, Mourad Benabdesselam, Wilfried Blanc. The Interplay Between Radiation-induced Attenuation, Photodarkening and Photobleaching at Pump Wavelength in Er-and Yb-doped Silica Optical Fibers. CIMTEC 2022, International Conferences on Modern Materials and Technologies, Jun 2022, Pérouse, Italy. hal-04584691

HAL Id: hal-04584691

https://hal.science/hal-04584691

Submitted on 23 May 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

Public Domain
The Interplay Between Radiation-induced Attenuation, Photodarkening and Photobleaching at Pump Wavelength in Er- and Yb-doped Silica Optical Fibers

Franck MADY*, Mourad BENABDESSELAM and Wilfried BLANC, Université Côte d'Azur, CNRS, INPHYNI UMR 7010, Nice, France

Radiation-induced attenuation (RIA) is the most detrimental effect in erbium- and ytterbium-doped silica fibers (EDF and YDF) operated in radiative environments. In amplifying conditions, RIA develops together with the pump-induced photobleaching (PB) and photodarkening (PD, YDF only) processes. The *measured RIA* then reflects a complex interplay between RIA, PD and PB. To allow a reliable treatment of RIA issues in fiber amplifier models, this interplay has still to be properly understood and modelled. This is the aim of this work. The RIA was measured at 980 nm in 1-2 cm-long fibers. Such short samples are free from amplification and ASE. They allow achieving well controlled and uniform pump power levels, thus releasing measurements from unwanted dependencies on length or pumping scheme. New remarkable properties are hence revealed, as the existence of local reversible RIA equilibrium levels, only determined by the couple dose rate-pump power. The interplay between RIA, PD and PB is also explicated. Local models are introduced for EDF and YDF that apparently include sufficient physics to reproduce all experimental features, qualitatively and quantitatively. The way these models complement and modify the set of equations used in standard amplifier simulations is presented.
The Interplay Between Radiation-induced Attenuation, Photodarkening and Photobleaching at Pump Wavelength in Er- and Yb-doped Silica Optical Fibers

Franck MADY*, Mourad BENABDESSELAM and Wilfried BLANC, Université Côte d'Azur, CNRS, INPHYNI UMR 7010, Nice, France

Radiation-induced attenuation (RIA) is the most detrimental effect in erbium- and ytterbium-doped silica fibers (EDF and YDF) operated in radiative environments. In amplifying conditions, RIA develops together with the pump-induced photobleaching (PB) and photodarkening (PD, YDF only) processes. The *measured RIA* then reflects a complex interplay between RIA, PD and PB. To allow a reliable treatment of RIA issues in fiber amplifier models, this interplay has still to be properly understood and modelled. This is the aim of this work. The RIA was measured at 980 nm in 1-2 cm-long fibers. Such short samples are free from amplification and ASE. They allow achieving well controlled and uniform pump power levels, thus releasing measurements from unwanted dependencies on length or pumping scheme. New remarkable properties are hence revealed, as the existence of local reversible RIA equilibrium levels, only determined by the couple dose rate-pump power. The interplay between RIA, PD and PB is also explicated. Local models are introduced for EDF and YDF that apparently include sufficient physics to reproduce all experimental features, qualitatively and quantitatively. The way these models complement and modify the set of equations used in standard amplifier simulations is presented.