Rare-Earth Doped Phosphate Glass Fibers

We report on the fabrication and characterization of phosphate fibers doped with Yb and Yb/Er ions. Optical amplification and laser operation are demonstrated in short-length devices

New Developments in Tellurite Glass Fibers

Recent developments on the manufacture of tellurite glass fibers are presented. Technical issues related to glass synthesis, preform manufacturing and fiber drawing as well as prospective of commercial exploitation are discussed

Analysis of Faraday effect in multimode tellurite glass optical fiber for magneto-optical sensing and monitoring applications

The design and fabrication of a tellurite glass multimode optical fiber for magneto-optical applications are presented and discussed. The analysis of the polarization shows that an optical beam, linearly polarized at the fiber input, changes to elliptically polarized with an ellipticity of 1∶4.5 after propagating down the fiber. However, the elliptical distribution remains unchanged with or without an applied magnetic field, demonstrating that no circular dichroism occurs within the fiber. The Verdet constant of the tellurite glass in the fiber is measured to be 28 0.5 rad · T ·m−1, diverging by less than 3% from the Verdet constant found on the same glass composition in bulk form. These results demonstrate the feasibility to develop reliable tellurite glass fibers by the preform drawing method for magneto-optical applications

Nd3+ Doped Phosphate Glass Optical Fibre Lasers

We report on the fabrication of three different phosphate glasses using a custom designed glass composition (P2O5 - Li2O - Al2O3 - B2O3 - BaO – PbO - MgO) with the aim to fabricate a Nd3+-doped double cladding optical fibre laser emitting at 1.06 μm. By changing properly the concentration and types of compounds present in our phosphate glass, the refractive indexes of the three glasses were adjusted in order to obtain an adequate numerical aperture between core and inner cladding, and between inner and outer cladding, while maintaining similar thermo-mechanical properties in view of the fibre drawing process. Physical and thermal properties of the glasses are presented and discussed. Spectroscopic properties of the core glass are described. In order to optimize Nd3+-doped fibre laser design, a numerical analysis of the lasers was performed and resulting design curves are presented. With the aim to test the feasibility of the double cladding optical fibre fabrication process and materials, a Yb3+/ Er3+ co-doped double cladding fibre based on the same glass host composition, was drawn and preliminary characterized

Phosphate glasses for fiber laser applications

There is a technological and industrial need for compact and intense sources in particular for those operating in pulsed mode operation. These types of sources are required for micromachining and marking applications using 1 um wavelength sources and also for lidar applications at eye-safe wavelengths in the 1.5 micron wavelength region. Phosphate glasses are particularly well suited for developing such devices. As rare earth ion hosts, they allow for achieving doping concentrations up to 1021 ions/cm3 without clustering and photordarkening. Their high phonon energy is also well suited for efficient emissions from Nd3+ and Yb3+ at 1 micron and the 1.5 micron emission from Er3+, using standard pumping schemes either at 808 nm or 980 nm. Thanks to this efficiency together with their outstanding thermo-mechanical properties, phosphate glasses can sustain high beam intensity. We present and discuss the development of rare earth doped phosphate glasses and fibers for laser and optical amplification applications operating in the 1 micron and 1.5 wavelength regions. Three host glass compositions have been designed for fabricating double clad structured fibers where the core glass composition was doped either with Nd3+, Yb3+ or Yb3+/Er3+ according to the operation wavelength foreseen. Single mode fibers with losses of 3.5 dB/m have been developed allowing for basic implementation of fiber lasers and optical amplifiers

Ho-doped tellurite glasses for emission in the mid infrared wavelength region

Tellurite glass is a suitable host for Ho3+ ions: fluorescence at 2.1 and 2.9 micron were explored by fabricating a single mode optical fiber and a series of bulk samples, respectively

Phosphate glass fibre scaffolds: tailoring of the properties and enhancement of the bioactivity through mesoporous glass particles

Novel bone glass fibre scaffolds were developed by thermally bonding phosphate glass fibres belonging to the P2O5-CaO-Na2O-SiO2-MgO-K2O-TiO2 system (TiPS2.5 glass). Scaffolds with fibres of 85 or 110µm diameter were fabricated, showing compressive strength in the range of 2–3.5 MPa, comparable to that of the trabecular bone. The effect of different thermal treatments and fibre diameters and length on the final scaffold structure was investigated by means of micro-CT analysis. The change of the sintering time from 30 to 60 min led to a decrease in the scaffold overall porosity from 58 to 21 vol.% for the 85µm fibre scaffold and from 50 to 40 vol.% when increasing the sintering temperature from 490 to 50°C for the 110µm fibre scaffold. The 85µm fibres resulted in an increase of the scaffold overall porosity, increased pore size and lower trabecular thickness; the use of different fibre diameters allowed the fabrication of a scaffold showing a porosity gradient.In order to impart bioactive properties to the scaffold, for the first time in the literature the introduction in these fibre scaffolds of a bioactive phase, a melt-derived bioactive glass (CEL2) powder or spray-dried mesoporous bioactive glass particles (SD-MBG) was investigated. The scaffold bioactivity was assessed through soaking in simulated body fluid. CEL2/glass fibre scaffold did not show promising results due to particle detachment from the fibres during soaking in simulated body fluid. Instead the use of mesoporous bioactive powders showed to be an effective way to impart bioactivity to the scaffold and could be further exploited in the future through the ability of mesoporous particles to act as systems for the controlled release of drugs