Structural origin of thermally induced refractive index changes in Yb³⁺/Al³⁺/P⁵⁺/F⁻‐co‐doped silica glass

Abstract

Yb 3+ -doped silica fiber has been an ideal gain medium in high-energy and high-power fiber laser applications. 1,2 The extreme increase in power density in the core leads to a strong nonlinear effect and even damage the fiber end facets in the conventional double-clad fibers. 3,4 To avoid these harmful effects, large-mode-area (LMA) designs have been performed owing to their large core diameter and effective mode area. 5,6 To maintain the single-mode operation, the refractive

Theoretical and experimental investigation of Al3+ ion-suppressed phase-separation structures in rare-earth-doped high-phosphorus silica glasses

“…According to the literature, the value of for the AlPO 4 glass is approximately 3.3 × 10 5 Hz, whereas the value of for both EYP10 and EYPA10 glasses is larger than 3.3 × 10 5 Hz. 40 This indicates that P–O–P linkages are present in both glasses, but the number of P–O–P linkages in the EYPA10 glass is much smaller than that in the EYP10 glass; this is consistent with the results obtained from the Raman spectrum. This result also demonstrates that the introduction of Al 3+ can effectively reduce the cross-linking of the phosphate network.…”

“…where k represents all the spins coupled with the observed spin j, b jk is the dipolar coupling constant between j and k, separated by distance r jk , and y is the phase rotation angle (01 r 2y r 3601), increased in discrete steps of 181. and EYPA10 glasses is larger than 3.3 Â 10 5 Hz. 40 This indicates that P-O-P linkages are present in both glasses, but the number of P-O-P linkages in the EYPA10 glass is much smaller than that in the EYP10 glass; this is consistent with the results obtained from the Raman spectrum. This result also demonstrates that the introduction of Al 3+ can effectively reduce the cross-linking of the phosphate network.…”

“…28,39 Among these, 480 cm À1 and 615 cm À1 are attributed to the Si-O-Si planar quaternary rings and planar ternary rings, respectively. 28,40 The bands at 430 cm À1 and 808 cm À1 are attributed to the bending vibration and symmetric stretching vibration of the Si-O-Si bond, respectively; the band near 720 cm À1 is related to the bending vibration of OQP-O; the vibrations near 1170 cm À1 are usually considered to be the ensemble of Si-O-Si, P-O-Al, Al-O-Si, Al-O-P, and P-O-Si bond vibrations; and the vibrations at 1320 cm À1 are mainly from the PQO double bond. 28,39,41 In Fig.…”

“…The average value of M 2 for all three Al species is approximately 4.8 Â 10 6 rad 2 s À2 , which is higher than the calibrated value of M 2 for AlPO 4 crystals (4.6 Â 10 6 rad 2 s À2 ), indicating that all Al atoms are exclusively bound by phosphorus-oxygen tetrahedra. 40,45 Almost all the Al atoms combine with P atoms to form Al-O-P linkages, which effectively relieve the local aggregation of phosphorus elements and substantially increase the ability of the EYPA10 glass to suppress phase separation. This is consistent with the results of the EYPA10 glass in the MD-simulated structures and TEM and HRTEM images.…”

Nanocrystalline Yb:YAG-Doped Silica Glass with Good Transmittance and Significant Spectral Performance Enhancements

“…It is necessary to reduce the doping content of Al 2 O 3 and Y 2 O 3 as these are the main components of YAG crystals. The 0.14Yb 2 O 3 -0.5Y 2 O 3 -0.87Al 2 O 3 -0.1BaO-98.39SiO 2 (YABS, in mol%) and 0.14Yb 2 O 3 -0.5Y 2 O 3 -0.87Al 2 O 3 -98.49SiO 2 (YAS, in mol%) glass were prepared using a modified sol-gel method [23] that was able to prepare glass of a large size, high homogeneity, and precise composition control, which facilitated the accurate analysis of the spectral and structural properties. BaO was introduced as a nucleating agent into the YABS glass to induce phase separation and crystallization of the glass [24], while a nucleating agent was not introduced into the YAS as a comparison sample.…”