Highly Birefringent Anti‐Resonant Hollow‐Core Fiber with a Bi‐Thickness Fourfold Semi‐Tube Structure

• Published in: Laser & photonics reviews 2022-05, Vol.16 (5), p.n/a
• Main Authors: Hong, Yi‐feng, Gao, Shou‐fei, Ding, Wei, Zhang, Xin, Jia, An‐qing, Sheng, Yu‐lin, Wang, Pu, Wang, Ying‐ying
• Format: Article
• Language: English
• Subjects: Birefringence; high birefringence; High resistance; hollow‐core fibers; micro‐structured fibers; Optical fibers; Polarization; polarization maintaining; Thickness
• ISSN: 1863-8880; 1863-8899
• DOI: 10.1002/lpor.202100365

The optical performance characteristics of anti‐resonant hollow‐core fibers (known as AR‐HCFs or ARFs) are improving rapidly, but the polarization maintaining issue with these fibers remains unresolved. Although a regular nonbirefringent ARF can maintain high polarization purity under static conditions, it cannot resist mechanical disturbances. In this work, by designing a bi‐thickness semi‐tube ARF structure with fourfold rotational symmetry, the first ARF with a level of birefringence close to 10−4 is fabricated. The proposed ARF features a combination of phase birefringence of 9.1 × 10−5, a minimum loss of 185 dB km−1, a bandwidth of 133 nm, and single‐mode operation. Furthermore, the ARF shows high resistance to fiber bending and wide‐range temperature variations, thus confirming that this carefully designed ARF can serve as a practical workhorse in polarization‐related optical fiber applications. An anti‐resonant hollow‐core fiber (ARF) with fourfold rotational‐symmetry and bi‐thickness semi‐tube structure is demonstrated, featuring a phase birefringence of almost 10−4, a minimum loss of 185 dB km−1, a bandwidth of 133 nm, and single‐mode operation. The high birefringence ensures great resistance to environmental perturbations, validating for the first time that ARF could be a practical workhorse in polarization‐related applications.