Detailed theoretical investigation of bending properties in solid-core photonic bandgap fibers.
Detailed theoretical investigation of bending properties in solid-core photonic bandgap fibers.
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DOI：
10.1364/oe.17.007615
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发表时间：
2009-04
期刊：
影响因子：
3.8
通讯作者：
T. Murao;K. Saitoh;M. Koshiba
中科院分区：
文献类型：
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作者：
T. Murao;K. Saitoh;M. Koshiba
本文研究了弯曲实芯光子带隙光纤（SC-PBGF）的特性。我们提出了一个近似的等效直波导（ESW）公式的光子带隙（PBG）的边缘，这是方便地看到定性的辐射（向心或离心辐射）主要发生和弯曲损耗的工作波长的影响。特别是，我们表明，弯曲引起的包层模式导致几个完整的或不完整的漏模耦合的核心模式和由此产生的损耗峰。此外，我们表明，包层模式的场分布的特点是由三个不同类型的蓝边，中间的差距，和红边波长的PBG，这是解释考虑包层布洛赫状态或共振条件，没有弯曲。接下来，我们研究弯曲损失的结构依赖性。特别是，我们证明了弯曲损耗依赖于包层环的数量。最后，通过研究光子带隙的排列顺序和纤芯结构对弯曲损耗的影响，讨论了紧弯曲结构。
In this paper, detailed properties of bent solid-core photonic bandgap fibers (SC-PBGFs) are investigated. We propose an approximate equivalent straight waveguide (ESW) formulation for photonic bandgap (PBG) edges, which is convenient to see qualitatively which radiation (centripetal or centrifugal radiation) mainly occurs and the impact of bend losses for an operating wavelength. In particular, we show that cladding modes induced by bending cause several complete or incomplete leaky mode couplings with the core mode and the resultant loss peaks. Moreover, we show that the field distributions of the cladding modes are characterized by three distinct types for blue-edge, mid-gap, and red-edge wavelengths in the PBG, which is explained by considering the cladding Bloch states or resonant conditions without bending. Next, we investigate the structural dependence of the bend losses. In particular, we demonstrate the bend-loss dependence on the number of the cladding rings. Finally, by investigating the impacts of the order of PBG and the core structure on the bend losses, we discuss a tight-bending structure.