Recent Developments in Rare-Earths Doped Nano-Engineered Glass Based Optical Fibers for High Power Fiber Lasers

Luminescent Properties and Optical Amplification of Erbium‐Doped Nano‐Engineered Scandium‐Phospho‐Yttria‐Alumina‐Silica Glass Based Optical Fiber

“…In such nano‐engineered glass based optical fiber, the basic silica material serves as a support for providing the optical and mechanical properties, whereas the spectroscopic properties would be controlled by the selected composition along with the type of incorporated NPs. The heat treatment stage involved annealing of the preform, usually above the glass‐transition temperature, found to be around 980 °C for such glass determined from DTA measurement . Growth of Er 2 O 3 doped nano‐crystallites depends on the metastable nature of Sc 2 O 3 ‐Y 2 O 3 ‐Al 2 O 3 silicate glass with the transformation of the stable crystalline state if enough thermal energy is available at two‐step nucleation and crystal growth process; the detailed mechanism has been reported earlier .…”

“…The heat treatment stage involved annealing of the preform, usually above the glass‐transition temperature, found to be around 980 °C for such glass determined from DTA measurement . Growth of Er 2 O 3 doped nano‐crystallites depends on the metastable nature of Sc 2 O 3 ‐Y 2 O 3 ‐Al 2 O 3 silicate glass with the transformation of the stable crystalline state if enough thermal energy is available at two‐step nucleation and crystal growth process; the detailed mechanism has been reported earlier . As scandium‐yttria–alumino silicate glass is heated above 1000 °C crystal nuclei − initially, tiny regions in the glass structure − begin to form.…”

“…The fabrication of Er doped nano‐engineered glass based optical fiber based on the incorporation of Al 2 O 3 , Y 2 O 3 , and Sc 2 O 3 into silica glass made to reduce RE clustering compared to pure silica glass along with improving fiber's spectroscopic properties. Insulation of REs ions from matrix vibrations is essential by appropriate material design of the surrounding ion site through the formation of phase‐separated NPs . This involves encapsulation of dopants inside glassy or crystalline NPs, embedded in the fiber glass.…”

“…The glass formers, SiO 2 and P 2 O 5 , were incorporated in the core matrix of the optical fiber preform through the MCVD process, where P 2 O 5 served as a nucleating agent that facilitates phase separation and assists generation of Er‐enriched nano‐crystallites . Selection of Sc 2 O 3 and Y 2 O 3 allows enhancing radiative transitions between electronic levels of RE's ions due to their low phonon energy compared to silica.…”

“…To evaluate the formation of phase‐separated particles by the thermal annealing process, we focused electron beam on and outside of the particles during TEM‐EDX analyses. The details about the fiber sample preparation for TEM analyses were described in detail earlier . The average doping distributions in the fiber core region were measured by means of Electron Probe Micro Analysis (EPMA) using a JEOL EPMA instrument.…”