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

Abstract

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.

Single-polarization Hybrid Hollow-core Anti-resonant Fiber Designs at 2 $μ$m

“…Achieving high-birefringence and single-polarization using the HC-ARF structure is a relatively new concept, which was first proposed in 2016 [18]. Recently, a few high-bireringence and single-polarization HC-ARF designs have been proposed in the near-IR regime mostly at 1550 nm or 1064 nm with different cladding arrangements and number of layers in the cladding structure [18]- [21]. High-birefringence and singlepolarization were achieved either by using multiple nested resonators [18], [21] or high index materials in the cladding [19], [20].…”

“…Recently, a few high-bireringence and single-polarization HC-ARF designs have been proposed in the near-IR regime mostly at 1550 nm or 1064 nm with different cladding arrangements and number of layers in the cladding structure [18]- [21]. High-birefringence and singlepolarization were achieved either by using multiple nested resonators [18], [21] or high index materials in the cladding [19], [20]. Most recently, a four-fold [21] and six-fold [22] symmetry bi-thickness HC-ARF were experimentally reported with outstanding optical performances.…”

“…High-birefringence and singlepolarization were achieved either by using multiple nested resonators [18], [21] or high index materials in the cladding [19], [20]. Most recently, a four-fold [21] and six-fold [22] symmetry bi-thickness HC-ARF were experimentally reported with outstanding optical performances. For example, in [21], a phase birefringence of 2.35 × 10 −5 and 9.1 × 10 −5 at 1550 and 1589 nm were achieved respectively.…”

“…Most recently, a four-fold [21] and six-fold [22] symmetry bi-thickness HC-ARF were experimentally reported with outstanding optical performances. For example, in [21], a phase birefringence of 2.35 × 10 −5 and 9.1 × 10 −5 at 1550 and 1589 nm were achieved respectively.…”

Giant Enhancement of Raman Scattering by a Hollow-Core Microstructured Optical Fiber Allows Single Exosome Probing

“…Microstructured optical fibers (MOFs), especially the most recent innovations of hollow-core anti-resonant optical fibers (HcARFs), provide solutions for breaking through the bottlenecks in areas of high-power transmission and high-efficiency optical waveguides . The featured light-guiding properties of ARFs determine their unique advantages such as broadband transmission, strong light–matter interaction, low delay, low nonlinearity, low transmission loss, and low dispersion, rendering them an ideal medium for communication, especially in the big data era.…”