Single-polarization single-mode hollow-core anti-resonant fiber with nested stadium-shaped tubes

Area of Science:

• Optical Fiber Technology
• Photonics and Nanotechnology

Background:

• Hollow-core anti-resonant fibers (HC-ARFs) offer unique light-guiding properties.
• Achieving high birefringence and polarization extinction ratio in HC-ARFs is crucial for polarization-maintaining applications.

Purpose of the Study:

• To propose and investigate a novel single-polarization HC-ARF with nested stadium-shaped tubes.
• To achieve single-mode, low-loss, and high-birefringence characteristics for advanced optical communications.

Main Methods:

• Utilizing nested stadium-shaped tubes to couple X-pol fundamental mode (FM) to cladding modes (CM).
• Confining Y-pol FM tightly within the fiber core to enhance polarization extinction ratio (PER).
• Coating the inner surface of the cladding tube with a silicon layer and optimizing structural parameters.

Main Results:

• Achieved high-order mode extinction ratios (HOMERs) of 530 and PERs of 15,135 at 1.55 µm.
• Demonstrated single-polarization bandwidths up to 220 nm and birefringence levels > 10⁻⁵.
• Obtained ultra-low confinement loss (CL) of 5.0 × 10⁻² dB/km and evaluated structural deformation tolerance.

Conclusions:

• The proposed silicon-coated HC-ARF with nested stadium-shaped tubes exhibits excellent single-polarization single-mode transmission characteristics.
• The fiber demonstrates high PER, large bandwidth, high birefringence, and low loss, suitable for practical applications.
• The study confirms the fiber's good bending characteristics and tolerance to structural deviations during manufacturing.