Ytterbium-Doped Double-Clad Fiber with High Uniformity of Concentration Distribution and Suppressed Photodarkening
Yongqing Yi,
Yize Shen,
Pengcheng Geng,
Rong Pan,
Shijie Xu,
Ruifang Luo
Affiliations
Yongqing Yi
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Yize Shen
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Pengcheng Geng
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Rong Pan
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Shijie Xu
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Ruifang Luo
Tianjin Key Laboratory of Special Optical Fiber Materials, The 46th Research Institute, China Electronics Technology Group Corporation, Tianjin 300220, China
Photodarkening (PD) effect in ytterbium-doped fiber (YDF) has a significant impact on the high-power operational stability of fiber lasers, which seriously hinders the power scaling. In this paper, the relationship between ytterbium ions uniformity and the photodarkening effect in the YDF was investigated, and the fabrication process allowing improving the ytterbium ions uniformity in the core of preforms for suppressing the photodarkening effect was developed. The Modified Chemical Vapor Deposition (MCVD) method combined with Chelate Vapor Deposition (CVD) technology was adopted for multi-layer fiber core deposition, and an all-gas-phase technical process was proposed to improve the ytterbium ions uniformity in the Al/P co-doped glass matrix. The 25/400 μm YDFs obtained by this technology achieved stable 3.5 kW laser output power for 8 h with suppressed PD and nonlinear effects.
