Hollow-core optical fibers are primarily categorized into photonic bandgap fibers, anti-resonant fibers, and Bragg fibers, each designed to guide light through a hollow core using distinct mechanisms.

Main Types of Hollow-Core Fibers

1. Photonic Bandgap Fibers (HC-PBGF) These fibers use a periodic microstructured cladding to create a photonic bandgap that confines light within the hollow core. They offer low loss, broad spectral transmission, and reduced nonlinear effects, making them suitable for telecommunications, high-speed data links, and precision sensing. Early designs include 7-cell and 13-cell structures, with modern refinements achieving losses as low as 1.2 dB/km . 2. Anti-Resonant Fibers (ARF) Also known as inhibited-coupling or single-ring “revolver” fibers, these fibers guide light by anti-resonant reflection from thin-walled tubes surrounding the core. They are simpler to fabricate than photonic bandgap fibers and can achieve broadband transmission with low latency, with modern designs reaching losses around 7.2 dB/km . Variants include Kagome-type fibers and negative-curvature fibers, optimized for minimal leakage and high power handling. 3. Bragg Fibers Bragg fibers use concentric dielectric layers in the cladding to reflect light back into the hollow core. They were among the earliest hollow-core designs and are primarily used in specialized applications where precise wavelength control is required .

Product Features and Variants

• Core Fill Options: Air, vacuum, or inert gases depending on application requirements .
• Protective Coatings: Similar to conventional fibers, HCFs include buffer layers to protect against mechanical stress and environmental damage .
• Low-Latency and High-Speed Variants: Designed for high-frequency trading, data center interconnects, and HPC networks, leveraging the faster light propagation in hollow cores .
• Specialized Conversion Fibers: Used to splice HCFs to conventional single-mode fibers without damaging the photonic cladding .

Summary

Hollow-core optical fiber products are distinguished by their guiding mechanism and structural design. Photonic bandgap fibers excel in low-loss, narrowband applications; anti-resonant fibers provide broadband, low-latency performance; and Bragg fibers offer precise wavelength control. Modern HCF products also include variants optimized for high-speed data, high-power transmission, and integration with conventional fiber networks, making them increasingly viable for commercial and research applications .