The apodization profiles have a great influence on the performance of apodized fiber Bragg gratings (AFBGs). Different apodization profiles can significantly affect the side lobe suppression ratio (SLSR) of AFBGs. In this work, we demonstrate theoretically and experimentally that the reduction of the local coupling strength of Gaussian AFBG edges can promote the side lobe suppression of the AFBG. Compared to the femtosecond laser line-by-line (LbL) inscription method of tailoring the track length, the two proposed different edge-weak-coupling LbL inscription methods improve the SLSR of the AFBGs by about 2.4 dB and 7.2 dB owing to the different reductions of the edge local coupling strength in the Gaussian apodization profiles. The SLSR of the direct-writing AFBG is expected to be improved further by optimizing the coupling strength profile.

中文翻译：

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边缘弱耦合飞秒激光逐线刻写技术用于制作变迹光纤光栅

变迹轮廓对变迹光纤布拉格光栅（AFBG）的性能有很大影响。不同的变迹曲线可以显着影响 AFBG 的旁瓣抑制比 (SLSR)。在这项工作中，我们从理论上和实验上证明了高斯AFBG边缘局部耦合强度的降低可以促进AFBG的旁瓣抑制。与定制轨道长度的飞秒激光逐行（LbL）刻写方法相比，两种不同的边缘弱耦合LbL刻写方法将AFBG的SLSR提高了约2.4 dB和7.2 dB，因为不同的高斯变迹剖面中边缘局部耦合强度的降低。通过优化耦合强度分布，直写 AFBG 的 SLSR 有望进一步提高。