Nested multibar cladding elements in negative curvature fibers for CO laser guidance

Abstract

A numerical study on the multi-bar nested cladding design of chalcogenide glass-based negative curvature hollow-core fiber was carried out to achieve a low-loss light guidance in the mid-infrared spectrum centered at 5.4 μm. Fiber design parameters were systematically optimized, and the effect of the nested bars on the confinement and total loss performance of a five-tubular cladding structure was investigated. An ultra-low transmission loss of 0.112 dB km−1 at 5.4 μm was achieved with As2Se3 triple-bar negative curvature fiber while maintaining low bending sensitivity. The design is also suitable for high transmission performance with alternative infrared glasses and can be potentially used for low-loss light guidance in a wide mid-infrared spectrum.