Nanoparticle-doped optical fibers are causing significant scientific interest in different application fields. Nanoparticle-doping
of silica glass layers during optical fiber preform fabrication was so far reported by sol-gel and solution doping
processes, by flame hydrolysis spraying and by pulling hollow cylinders from nanoparticle suspensions. A new method
for fabrication of high quality nanoparticle-doped fibers is suggested.
Proposed method is based on "flash vaporization" deposition process, previously reported as method to fabricate rare
earth- and metal ion-doped specialty optical fibers. Experiments were made where SiO2 layers were deposited using
"flash vaporization"-equipped MCVD system, adding vapors carrying metal or oxide nanoparticles into deposition zone.
Analysis of produced preforms confirms presence of nanoparticles in deposited layers, albeit with low deposition rate
due to weak thermophoretic forces acting on very small particles or agglomerations. Based on results, a number of
improvements were suggested and implemented in fabrication process, device design and choice of precursor materials.
"Flash vaporization" method was demonstrated as suitable method for deposition of nanoparticles in silica layers,
permitting in-situ fabrication of complete preforms, providing easy upgrade path for existing MCVD and OVD
deposition systems and allowing simultaneous co-doping by a wide range of other co-dopants.
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