A new terahertz (THz) polarization beam splitter (PBS) based on cyclic olefin copolymer (COC) photonic crystal fiber (PCF) with a simple structure is proposed. The dual cores are achieved by introducing six circular air holes in two rows of upper and lower symmetry into the fiber core. The mode coupling characteristics between the even and odd modes for the proposed dual-core PBS are investigated using the time-domain finite-difference (FDTD) method and coupled-mode theory. The influence of geometrical structure parameters on the PBS performance is analyzed. The numerical simulation results reveal that when the incident light frequency is 0.6 THz and the PBS length is 53.88 mm, the bandwidths of 0.0217 THz (from 0.5895 THz to 0.6112 THz) and 0.0225 THz (from 0.5908 THz to 0.6133 THz) are obtained for the x and y-polarization modes, respectively. The highest polarization extinction ratios (ERs) are 114.5 dB and 72.3 dB for the x and y-polarization modes, respectively. The simple structure and wide bandwidth make the proposed PBS will find extensive applications in THz communication, imaging, sensing, metrology, and microscopy.

提出了一种基于环烯烃共聚物（COC）光子晶体光纤（PCF）的新型太赫兹（THz）偏振分束器（PBS），结构简单。双芯是通过在纤芯中引入上下两排对称的六个圆形气孔来实现的。使用时域有限差分 (FDTD) 方法和耦合模式理论研究了所提出的双核 PBS 的偶数和奇数模式之间的模式耦合特性。分析了几何结构参数对PBS性能的影响。数值模拟结果表明，当入射光频率为0.6 THz，PBS长度为53.88 mm时，获得了0.0217 THz（0.5895 THz至0.6112 THz）和0.0225 THz（0.5908 THz至0.6133 THz）的带宽X和y偏振模式，分别。对于x和y偏振模式，最高偏振消光比 (ER) 分别为 114.5 dB 和 72.3 dB 。简单的结构和宽的带宽使得所提出的 PBS 将在太赫兹通信、成像、传感、计量学和显微镜学中找到广泛的应用。