Record Low Loss Hollow Core Fiber for the 1μm Region

Hollow core (HC) antiresonant fibers (ARFs) offer potential for low optical loss, low glass-mode overlap, and wide transmission bandwidth that could cover regions from the UV to the Mid-IR, and be optimized to work in the 1μm and 1.55μm bands [1,2]. The optical properties of ARFs depend mainly on the arrangement and thickness of the core surrounding membranes. To date, the state-of-the-art optical loss in a 1μm-guiding HCF is reported by Maurel et al. [3] in a Kagome fiber, showing 8.5dB/km at the Nd-Yb:YAG laser wavelengths. Other low loss results at the 1μm region have been reported by Wheeler et al. [4] showing 12.3dB/km at 1010nm in a Kagome HCF; Chen et al. [5] showing 12.3dB/km at 1047nm in a 37-cell photonic bandgap fiber (PBGF); and Debord et al. [6] showing a loss of 8–20dB/km in the 800–1200nm region in tubular lattice HCF. The addition of smaller nested tubes to the known ‘tubular’ hollow core ARFs can considerably reduce their optical loss, allowing in principle a HC-Nested Antiresonant Nodeless Fiber (NANF) to achieve total loss values lower than conventional solid fibers [7]. Recent NANF results showed loss of 1.3dB/km at 1450nm (Bradley et al. [8]).