Towards Large-Mode-Area fibers fabricated by the full vapor-phase SPCVD process

Alexandre Barnini (1) , Thierry Robin (1) , Daniel Caurant (2) , Thierry Gotter (1) , Gérard Aka (2) , Cedric Guyon (2) , Pascal Guitton (1) , Ronan Montron (1) , Arnaud Laurent (1)

1 iXBlue Photonics
2 IRCP - Institut de Recherche de Chimie Paris

Large-Mode-Area (LMA) fibers are key elements in modern high power fiber lasers operating at 1 µm. LMA fibers are highly ytterbium-doped and require a fine control of the core refractive index (RI) close to the silica level. These low RI have been achieved with multi-component materials elaborated using a full-vapor phase Surface Plasma Chemical Vapor Deposition (SPCVD) process, enabling the fabrication of large core diameter preforms (up to 4 millimeters). Following the technology demonstration, presented in Photonics West 2017, with results on 10/130 (core-to-clad diameters (in µm) ratio) fibers, this paper aims to present updated results obtained for double-clad 11/130, 20/130 and 20/400 LMA fibers, with numerical apertures at, respectively, 0.08 and 0.065. The study is based on aluminosilicate core material co-doped either with fluorine or phosphorus to achieve optimal radial RI tailoring. The fiber produced exhibit low background losses (<20dB/km at 1100nm) and high power conversion efficiencies, up to 74% for output powers of 100W limited by our test setup. The Gaussian beam quality has been evaluated using the M² measurement. Photodarkening behavior will be discussed for both fluorine and phosphorus-doped aluminosilicate materials and particularly the use of cerium as co-dopant. The SPCVD technology can indeed be used for the production of Yb-doped LMA fibers. Current development is now focused on other rare-earth doped fibers.

Mots clés: Rare earth-doped fiber; ytterbium; optical amplifier; laser; aluminosilicate fibers

Domaines: Chimie; Matériaux

Alexandre Barnini, Thierry Robin, Daniel Caurant, Thierry Gotter, Gérard Aka, et al.. Towards Large-Mode-Area fibers fabricated by the full vapor-phase SPCVD process. Photonics West 2018, Jan 2018, San Francisco, United States. ⟨hal-02327630⟩