Zero–group-velocity modes in chalcogenide holey photonic-crystal fibers

Abstract

We demonstrate that a holey photonic-crystal fiber with chalcogenide-glass index contrast can be designed to have a complete gap at a propagation constant β=0 that also extends into the non-zero β region. This type of bandgap (previously identified only at index contrasts unattainable in glasses) opens up a regime for guiding zero—group-velocity modes not possible in holey fibers with the more common finger-like gaps originating from β→∞. Such modes could be used to enhance nonlinear and other material interactions, such as for hollow-core fibers in gas-sensor applications.