Design of photonic band gap fibers with suppressed higher-order modes: towards the development of effectively single mode large hollow-core fiber platforms.
Design of photonic band gap fibers with suppressed higher-order modes: towards the development of effectively single mode large hollow-core fiber platforms.
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DOI：
10.1364/oe.14.007342
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发表时间：
2006-08
期刊：
影响因子：
3.8
通讯作者：
K. Saitoh;N. Florous;T. Murao;M. Koshiba
中科院分区：
文献类型：
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作者：
K. Saitoh;N. Florous;T. Murao;M. Koshiba
本研究的目的是提出并从理论上证明大空芯光子带隙光纤（PBGF）中高阶模的有效抑制，主要用于低损耗数据传输平台和/或高功率传输系统。提出的设计策略是基于中心空芯模式与缺陷外芯模式的折射率匹配机制。通过在具有6重对称性的PBGF的包层中结合若干空气芯，可以将对应于高阶模的光谐振耦合到外芯中，从而与基模相比显著增加了高阶模的泄漏损耗，从而使我们提出的设计以具有偏振无关传播特性的有效单模方式操作。基于精确的有限元模态求解器的详细PBGF分析确保了该过程的验证。大量的数值计算结果表明，高阶模式的泄漏损失可以提高至少2个数量级的水平相比，基本模式。我们的研究有望消除发展大芯单模空芯光纤的一个重要障碍，从而使它们能够超越传统光纤的衰减。
The objective of the present investigation is to propose and theoretically demonstrate the effective suppression of higher-order modes in large-hollow-core photonic band gap fibers (PBGFs), mainly for low-loss data transmission platforms and/or high power delivery systems. The proposed design strategy is based on the index-matching mechanism of central air-core modes with defected outer core modes. By incorporating several air-cores in the cladding of the PBGF with 6-fold symmetry it is possible to resonantly couple the light corresponding to higher-order modes into the outer core, thus significantly increasing the leakage losses of the higher-order modes in comparison to the fundamental mode, thus making our proposed design to operate in an effectively single mode fashion with polarization independent propagation characteristics. The validation of the procedure is ensured with a detailed PBGF analysis based on an accurate finite element modal solver. Extensive numerical results show that the leakage losses of the higher-order modes can be enhanced in a level of at least 2 orders of magnitude in comparison to those of the fundamental mode. Our investigation is expected to remove an essential obstacle in the development of large-core single-mode hollow-core fibers, thus enabling them to surpass the attenuation of conventional fibers.