Design, Production, and Characterization of a Large-Mode Area Tubular Inhibited-Coupling Guiding Hollow-Core Fiber with Low Dispersion

Since the first demonstration [1], hollow-core fibers have been considered as the only presently known solution for the flexible delivery of beams of high peak-power ultrafast lasers. This is achieved thanks to a low power overlap between the core-guided modes and the fiber glass cladding (in the range of 10⁻⁴ to 10⁻⁶) [2]. For the beam delivery in production systems, it is necessary for the fibers not to alter the pulse characteristics during propagation. Besides nonlinear effects and dispersion caused by the gas inside the fiber core, which can be mitigated by filling the fiber core with noble gases or applying a vacuum to the core, the chromatic dispersion of the fiber itself is a main contributor to changes in the pulse duration. In general, a larger fiber core leads to a reduced chromatic dispersion.