Short-length microstructured phosphate glass fiber lasers with large mode areas

Silver metaphosphate glass wires inside silica fibers--a new approach for hybrid optical fibers

Phosphate glasses represent promising candidates for next-generation photonic devices due to their unique characteristics, such as vastly tunable optical properties, and high rare earth solubility. Here we show that silver metaphosphate wires with bulk optical properties and diameters as small as 2 µm can be integrated into silica fibers using pressure-assisted melt filling. By analyzing two types of hybrid metaphosphate-silica fibers, we show that the filled metaphosphate glass has only negligible higher attenuation and a refractive index that is identical to the bulk material. The presented results pave the way towards new fiber-type optical devices relying on metaphosphate glasses, which are promising materials for applications in nonlinear optics, sensing and spectral filtering.

Ytterbium-Phosphate Glass for Microstructured Fiber Laser

In the paper, we report on the development of a synthesis and melting method of phosphate glasses designed for active microstructured fiber manufacturing. Non-doped glass synthesized in a P₂O₅-Al₂O₃-BaO-ZnO-MgO-Na₂O oxide system served as the matrix material; meanwhile, the glass was doped with 6 mol% (18 wt%) of Yb₂O₃, as fiber core. The glasses were well-fitted in relation to optical (refractive index) and thermal proprieties (thermal expansion coefficient, rheology). The fiber with the Yb³⁺-doped core, with a wide internal photonic microstructure for a laser pump, as well as with a high relative hole size in the photonic outer air-cladding, was produced. The laser built on the basis of this fiber enabled achieving 8.07 W of output power with 20.5% slope efficiency against the launched pump power, in single-mode operation M² = 1.59, from a 53 cm-long cavity.

Ion-exchanged Er3+/Yb3+ co-doped waveguide amplifiers longitudinally pumped by broad area lasers

A multimode pumping scheme for Er(3+)/Yb(3+) co-doped waveguide amplifiers based on broad area lasers at around 980 nm is presented. The proposed amplifier is fabricated by ion-exchange (IE) technique on silicate and phosphate glasses. The highly efficient energy transfer from Yb(3+) to Er(3+) ions, combined with the use of low cost and high power broad area laser, allows the realization of high performance and cost-effective integrated amplifiers. The structure has been designed and numerically studied using a 3D finite element modelling tool, and over 3 dB/cm small signal gain has been predicted for an optimized amplifier. Preliminary characterization of an amplifier structure provides a first experimental evidence of the novel multimode longitudinal pumping.

Yb3+:YAG silica fiber laser

We demonstrate a compact, room-temperature, cw Yb(3+):Y(3)Al(5)O(12) silica (Yb(3+):YAG silica) fiber laser grown by the codrawing laser-heated pedestal growth technique. A slope efficiency of 76.3% was achieved from a 7 mm Yb(3+):YAG silica fiber, corresponding to an extracted power of nearly 1 W/cm. A laser side-mode suppression ratio of 70 dB was obtained with a 3 dB linewidth of 0.15 nm. Additionally, the propagation loss and emission cross section were determined by analyzing the lasing thresholds and slope efficiencies.

Investigation of modal properties of microstructured optical fibers with large depressed-index cores

We present what is, to the best of our knowledge, the first systematic study on how negative core-cladding index difference influences microstructured optical fiber's modal behavior. Single-mode lasing has been realized for short-length cladding-pumped phosphate glass microstructured fibers with large depressed-index Er(3+)-Yb(3+)-codoped cores.