We present a type of few-period helically twisted all-solid photonic bandgap fiber (AS-PBGFs). The helical structure leads to orbital resonance of a cladding rod light, which couples with the core mode. A two-period twist structure exhibits an extremely strong resonant dip of up to 30 dB. A series of samples with twist periods of 3.31–7.92 mm (yielding twist rates of $1.90-0.79\mathrm{rad}\cdot {\mathrm{mm}}^{-1}$) in association with different resonance orders are fabricated and demonstrated. The inherent physical mechanism underlying the resonance is analyzed. Moreover, the responses of the resonance to mechanical torsion, strain, and temperature are investigated. The twisted AS-PBGFs feature high reproducibility, stability, and robustness, and have great potential in tunable in-fiber filters and sensors.

中文翻译：

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短周期螺旋扭曲全固态光子带隙光纤

我们提出了一种短周期的螺旋扭曲全固态光子带隙光纤（AS-PBGFs）。螺旋结构导致包层棒光的轨道共振，该共振与芯模耦合。两周期的扭曲结构表现出高达30 dB的极强的共振衰减。一系列样品的扭曲周期为3.31–7.92 mm（屈服速率为$1.90-0.79\mathrm{拉德}\cdot {\mathrm{毫米}}^{-\mathrm{1个}}$结合不同的共振阶数进行制作和演示。分析了共振的内在物理机制。此外，研究了共振对机械扭转，应变和温度的响应。扭曲的AS-PBGF具有高重现性，稳定性和鲁棒性，并且在可调谐光纤滤波器和传感器方面具有巨大潜力。