Abstract We present a new scheme of dual-core THz fiber for tunable polarization splitter based on the mode coupling theory. Each elliptical polymer core is modified with two elliptical air holes, which is helpful for high modal birefringence and low transmission loss. Due to different coupling lengths for x and y polarizations, the two orthogonal polarizations can be easily separated in an appropriate transmission length. Characteristics of the proposed fiber are discussed numerically in detail, including modal birefringence, effective material absorption loss, coupling and splitting length, transmission loss, extinction ratio, tunability. For the THz polarization splitters, 0.865 cm splitting length is numerically demonstrated at the operation frequency of 1 THz. An efficient tuning method is provided that the operation frequency can be tuned by the applied pressure. This tuning method extends the operation frequency bandwidth from 0.9 to 1 THz in the fixed splitting length. This proposed pressure-tuning THz fiber polarization splitter has potential applications in the field of on-chip integrated THz polarization devices and in-fiber integrated optical devices.

中文翻译：

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用于太赫兹范围内可调谐偏振分束器的双芯光纤

摘要 我们提出了一种基于模式耦合理论的可调谐偏振分束器双芯太赫兹光纤的新方案。每个椭圆形聚合物纤芯都修饰有两个椭圆形气孔，有助于高模态双折射和低传输损耗。由于 x 和 y 极化的耦合长度不同，两个正交极化可以很容易地以适当的传输长度分开。详细讨论了所提出光纤的特性，包括模式双折射、有效材料吸收损耗、耦合和分裂长度、传输损耗、消光比、可调性。对于太赫兹偏振分光器，在 1 太赫兹的工作频率下，0.865 厘米的分裂长度被数值证明。提供了一种有效的调谐方法，可以通过施加的压力来调谐工作频率。这种调谐方法在固定分裂长度内将工作频率带宽从 0.9 扩展到 1 THz。这种压力调谐太赫兹光纤偏振分束器在片上集成太赫兹偏振器件和光纤集成光学器件领域具有潜在应用。