Effects of fluorine on the properties of Yb/Ce co-doped aluminosilicate preforms prepared by MCVD with organic chelate precursor doping technique

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• 作者：Weinan Li ; Rong Luo ; Chao Li ; Song Gao ; Chang Chang ; Chaoqi Hou ; ^{houchaoqi@opt.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Baoyin Zhao ; ^{joseph.zhao@opt.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Raman spectra ; Chelate precursor ; Yb/Ce codoped silica glass ; Antisymmetric stretching vibrations
• 刊名：Journal of Non-Crystalline Solids
• 出版年：2016
• 出版时间：1 October 2016
• 年：2016
• 卷：449
• 期：Complete
• 页码：119-124
• 全文大小：781 K

文摘

Co-doped Yb/Ce aluminosilicate fiber preforms with less than 1&#xA0;Wt% fluorine were prepared by MCVD with organic chelate precursor doping technique at 1400&#xA0;°C. Fluorine content characterized by electron probe microanalysis decreased with increasing SiF₄ flow and flow ratio of SiF₄/SiCl₄. Under maximum SiF₄ flow the concentrations of Yb₂O₃ and CeO₂ in the perform core were only as much as 17% and 25% under minimum SiF₄ flow, respectively, but smaller refractive index change was only shown in fiber core. The reason was that the reaction of SiF₄ with Al₂O₃,Yb₂O₃,CeO₂ were intensified with increasing flow ratio of SiF₄/SiCl₄ and then resulted in producing more exhaust gas such as AlF₃, YbF₃ and CeF₄. Raman spectra of core glasses with <&#xA0;0.5&#xA0;Wt% fluorine present different Raman shifts from F doped silica glass with 1–3.3&#xA0;Wt% fluorine: 945&#xA0;cm^−&#xA0;1 of Sixl.gif" class="glyphImg imgLazyJSB">F stretching bond was not observed, and with growth of fluorine content antisymmetric stretching vibrations of Si-O-Si linkages split from an envelope of 1188&#xA0;cm^−&#xA0;1 into two peaks or three peaks shifted higher frequency. At the same time, Boson peak near 125&#xA0;cm^−&#xA0;1 shifted to lower frequency. They were attributed to some minor changes of glass's network structure due to introducing lower fluorine into core glasses. On base of bonding energy measured by X-ray photoelectric spectroscopy, the plane graph describing the complex bonding distribution with F in core was supplied to in order to illustrate network structure change.