Chirped multilayer hollow waveguides with broadband transmission

The guiding of broadband light in a hollow core is of large importance in several fields, especially for transmission and nonlinear spectral transformations of high-power laser pulses. Standard hollow fibers with a solid dielectric cladding guide light by reflection from a higher-index interface and are thus inherently leaky with relatively high loss. Guiding in bandgap or omniguide waveguides is provided by the bandgap in the cladding (determined by the layer thickness) and is therefore intrinsically narrow-band. The key idea of this contribution is to vary ("chirp") the thicknesses of the multilayer dielectric waveguide with layer number, which results in shifting bandgap position over the layers and thus a moderate loss over a broad spectral region.