Dopant Segregation in Single-Crystal Optical Fiber Grown via the Laser-Heated Pedestal Growth Technique

Conference · Sun Apr 21 04:00:00 EDT 2024

OSTI ID:2339583

Lander, Gary ^[1]; Wuenschell, Jeffrey ^[1]; Lim, Geunsik ^[1]; Karki, Dolendra ^[2]; Hong, Jun Young ^[2]; Ohodnicki, Jr., Paul ^[2]; Buric, Michael ^[3]

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1. NETL Site Support Contractor, National Energy Technology Laboratory
2. University of Pittsburgh
3. NETL

Single crystal (SC) optical fiber has promising potential to be used for optical fiber sensing applications in harsh conditions due to its robustness to high temperature, high radioactivity, and resistance to chemical corrosion as compared to optical sensors using silica fiber. However, SC fiber grown via the laser-heated pedestal growth (LHPG) technique innately does not have a core-cladding structure found in standard optical fiber, resulting in optical losses. In this work we investigate optimization of the growth parameters of a two LHPG process used to grow SC fiber with a graded index via introduction of dopants to the feedstock material. Feedstock material is fabricated with the first LHPG device, then sol-gel dip-coated to create outer films of dopant material. The dip-coated feedstock is used to grow SC fiber in which segregation of the dopant constituents occurs, resulting in a graded index of refraction across the fiber, and an effective core-cladding structure. Hardware and software improvements to both LHPG systems are presented and the growth parameters for short pieces of ~320-330 μm diameter YAG fiber has been established. Characterization techniques/procedures have also been established for future grown SC fiber. These improvements and preparations are anticipated to result in a significant increase in grown fiber quality with a similar growth rate to that previously established.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
• Sponsoring Organization: FE - USDOE Office of Fossil Energy and Carbon Management (FECM)
• OSTI ID: 2339583
• Country of Publication: United States
• Language: English