Radiation-hardened Erbium-doped optical fibers and amplifiers for future high-dose space missions
Résumé
We present a new class of Erbium-doped optical fibers: the Hole-Assisted Carbon-Coated, HACC fibers. Optical fibers with this particular structure have been made by iXFiber on the basis of an appropriate choice of codopants in their core and claddings. By using an additional pre-treatment with deuterium (D2) authorized by the HACC structure, we demonstrated that this new type of fiber presents a strongly enhanced radiation resistance compared to the other types of erbium-doped optical fibers studied in litterature. We also built an Erbium-doped Fiber Amplifier (EDFA) with one of these HACC fibers and compared its radiation response to the one of the same fiber without the HACC structure and D2 loading. We tested the performances of this EDFA under -rays and characterize its gain degradation up to 315 krad. Before irradiation, the amplifier presents a gain of about 31 dB that is comparable to the optical performances of amplifiers based on HACC fibers without the D2 pre-treatment and the HACC structure. During irradiation, our results demonstrate that the tested amplifier is nearly unaffected by radiations. Its gain slowly decreases with the dose, of about -2.2×10-3 dB/krad. This strong radiation resistance (enhancement of a factor of ×10) compared to the radiation tolerant EDFA) will authorize the use of HACC doped fibers and amplifiers for various applications in space, both for space missions associated with low or large irradiation doses.