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arXiv · 2603.17700

Two-Step Tapering-Collapse Method Enables Element-Interdiffused Cladding for Enhanced Laser Amplification in Yb:YAG Single Crystal Fibers

Xiangfei Zhu·Xiaofei Ma·Chenxin Gao·Tao Wang·Zhen Huang·Jiajia Zeng·Dongran Shi·Xuanfeng Zhou·Baolai Yang·Zilun Chen·Hu Xiao·Feng Xiong·Pengfei Ma·Jian Zhang·Zhitai Jia·Zefeng Wang·Xutang Tao
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Abstract

The development of high-power single crystal fiber (SCF) lasers is critically hindered by the lack of a reliable cladding scheme to confine the optical mode and ensure beam quality. Here, we propose and demonstrate a two-step tapering-collapse method for the first time to fabricate a high-quality cladding on Yb:YAG SCFs based on elemental interdiffusion. This in-situ formed crystalline transition layer with a graded refractive index effectively suppresses lattice mismatch and abruptly mitigates core-cladding interfacial stress. Consequently, the numerical aperture of the SCF is significantly reduced from 0.280 to 0.199. In a master oscillator power amplifier configuration, the clad SCF delivers a remarkable 46.7% enhancement in slope efficiency compared to its bare counterpart, accompanied by a substantially improved near-field beam profile. This work establishes a facile and effective route to high-performance clad SCFs, unlocking their full potential for next-generation extreme-condition lasers.

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Xiangfei Zhu, Xiaofei Ma, Chenxin Gao, Tao Wang, Zhen Huang, Jiajia Zeng, Dongran Shi, Xuanfeng Zhou, Baolai Yang, Zilun Chen, Hu Xiao, Feng Xiong, Pengfei Ma, Jian Zhang, Zhitai Jia, Zefeng Wang, Xutang Tao. 2026-03-18. Two-Step Tapering-Collapse Method Enables Element-Interdiffused Cladding for Enhanced Laser Amplification in Yb:YAG Single Crystal Fibers. https://arxiv.org/abs/2603.17700

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