Three-Dimensional Chirped High-Contrast Grating Hollow-Core Waveguide

A 3-D chirped high-contrast grating hollow-core waveguide (HCG-HW) exhibits highly efficient 2-D (transverse and lateral) light confinement. Compared with step-index ones, laterally chirped HCG-HWs (graded index) can pronouncedly reduce the propagation loss (>; 10×) without compromising the lateral index contrast. Simulation results show that a propagation loss as low as 0.04 dB/cm can be achieved. For a chirped HCG-HW with a 6-μm core height, it exhibits 30and 141-nm spectral widths for 0.1and 1-dB/cm loss requirements. The chirped HCG-HW also shows an ultralow nonlinear coefficient, which is on the order of 10 -5 /W/m.