Polarization-maintaining terahertz anti-resonant fibers based on mode couplings between core and cladding
Shuai Sun, Wei Shi, Quan Sheng, Zhongbao Yan, Shuai Zhang, Junxiang Zhang, Chaodu Shi, Guizhong Zhang, Jianquan Yao
Abstract
This study numerically investigated the index-induced mode coupling between the fundamental mode in core and the fundamental mode in cladding tubes in THz anti-resonant fibers (ARFs), and then, this index-induced mode coupling was applied for designing polarization-maintaining ARFs. Simulated results indicate that in the polarization-maintaining ARFs based on index-induced mode coupling, when the core diameter approaches the diameter of cladding tubes, ARFs can realize a birefringence which maintaining the polarization of incident light. Besides, the birefringence property which is realized by deforming the core boundary or categorizing the core boundary into two orthometric anti-resonant boundaries can be enhanced by the index-induced mode coupling. Based on the index-induced mode coupling, this paper proposed three compact polarization-maintaining ARFs, and the highest birefringence index exceeded 4 × 10−4.