We report on the fabrication of filament damages in Yb-doped phosphate glass by femtosecond laser pulses. The uneven index modification was obtained using a 20× optical microscope objective with 0.4 numerical apertures. The multimode fields of original channel waveguides were investigated and in good agreement with the simulation results, whose structures can be regarded as a kind of beam splitters. Under the optical pump at 976 nm, the end region of the original filament shows continuous wave laser oscillation. The elongated and uniform filaments were fabricated by introducing a circular aperture, so that the guiding performance of tradition-channel single mode was achieved. Both large-mode-area waveguides are expected to find applications in optical communications and high-power lasers and amplifiers.

中文翻译：

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掺镱磷酸盐玻璃中的灯丝损伤和通道波导制造

我们报告了通过飞秒激光脉冲在掺镱的磷酸盐玻璃中制造灯丝损伤。使用具有 0.4 数值孔径的 20 倍光学显微镜物镜获得不均匀指数修正。研究了原始通道波导的多模场，与仿真结果吻合良好，其结构可视为一种分束器。在 976 nm 的光泵下，原始灯丝的末端区域显示出连续波激光振荡。通过引入圆形孔径制造细长均匀的灯丝，从而实现传统通道单模的引导性能。这两种大模面波导都有望在光通信和高功率激光器和放大器中找到应用。