Low-loss multi-mode anti-resonant hollow-core fibers

Area of Science:

• Optical Fiber Technology
• Photonics
• Materials Science

Background:

• Anti-resonant hollow-core fibers (AR-HCFs) offer unique light-guiding properties.
• Developing multi-mode AR-HCFs is crucial for applications requiring high power handling.
• Existing multi-mode fibers often face challenges with loss and mode control.

Purpose of the Study:

• To fabricate and characterize a novel multi-mode anti-resonant hollow-core fiber (AR-HCF).
• To investigate the transmission properties, including attenuation and bend loss.
• To explore the modal properties and potential applications of the developed AR-HCF.

Main Methods:

• Fabrication of AR-HCF with 18 fan-shaped resonators.
• Characterization of transmission properties at 1 µm wavelength.
• Modal analysis using the S² imaging technique.
• Scaling the design for longer wavelength transmission (> 4 µm).

Main Results:

• Achieved low attenuation (< 0.1 dB/m at 1 µm) and bend loss (< 0.2 dB/m at 8 cm bend radius).
• Identified seven LP-like modes in a 23.6 m long multi-mode AR-HCF.
• Extended the transmission window beyond 4 µm by scaling the fiber design.
• Demonstrated a core diameter to wavelength ratio up to 85 in the lowest transmission band.

Conclusions:

• The fabricated multi-mode AR-HCF exhibits excellent low-loss and low-bend-loss performance.
• The fiber supports multiple modes, making it suitable for various applications.
• Potential applications include high-power laser light delivery requiring high coupling efficiency and laser damage threshold.