Applications for hollow-core photonic-crystal fibers (HC-PCFs) continue to proliferate as fabrication processes improve and insertion losses decrease (see www.laserfocusworld.com/articles/274709 and www.laserfocusworld.com/articles/250395). Researchers at the University of Bath (Bath, England) have now overcome the fundamental narrow transmission bandwidth of most HC-PCFs by demonstrating a kagome (Star of David)-structured HC-PCF with tight confinement of light in the core region that spans a broad wavelength range in the visible and near-IR portions of the spectrum.
To create the core defect-which ranges in diameter from 22 µm for a single-cell-defect fiber core to 65 µm for a 19-cell-defect fiber core-shorter capillaries are stacked on the interior of both ends of a solid-stacked form, leaving a kagome-shaped air gap in the middle. For the 19-cell kagome fiber, the transmission bandwidth covers a 250 nm range in the visible (approximately 550 to 800 nm) and a 700 nm range in the IR (approximately 1100 to 1800 nm), enabling a range of new applications in gas sensing, high-harmonic generation, and soliton delivery. Contact Fetah Benabid at [email protected].