In this paper, we studied the basic characteristics of tilted fiber Bragg gratings (TFBGs), inscribed line-by-line. Experimental results showed that if the TFBGs were located within different planes parallel to the fiber axis, the spectra performed differently. For 2°TFBG, if it was located near the central plane, the Bragg resonance was stronger than ghost mode resonance, and the order reversed if it was located near the boundary between core and cladding. As the tilted angle increased, the range of cladding mode resonance increased. When the tilted angle was larger than 12°, the birefringence effect was observed. Based on the birefringence phenomenon, torsion characteristics were experimentally studied; the sensitivity was about 0.025 dB/degree in the linear variation range. The harmonic order of TFBGs also affected the transmission spectrum. Leaky mode resonance was observed in the 8th order TFBG, and torsion (or polarization) influenced the spectrum of the 8th order TFBG. Our research represented the theory of line-by-line inscribed TFBGs and provided an inscription guidance for TFBGs.

中文翻译：

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使用飞秒激光逐行刻写倾斜光纤布拉格光栅的磨损和表征

在本文中，我们研究了逐行刻划的倾斜光纤布拉格光栅 (TFBG) 的基本特性。实验结果表明，如果 TFBG 位于平行于光纤轴的不同平面内，则光谱表现不同。对于2°TFBG，如果它位于中心平面附近，布拉格共振比鬼模共振更强，如果它位于纤芯和包层之间的边界附近，则顺序相反。随着倾斜角的增加，包层模式共振的范围增加。当倾角大于12°时，观察到双折射效应。基于双折射现象，对扭转特性进行了实验研究；在线性变化范围内，灵敏度约为 0.025 dB/度。TFBG 的谐波阶次也影响传输频谱。在 8 阶 TFBG 中观察到泄漏模式共振，并且扭转（或极化）影响了 8 阶 TFBG 的光谱。我们的研究代表了逐行刻录 TFBG 的理论，并为 TFBG 提供了刻录指导。