A new kind of semi-slow light photonic crystal waveguides with large delay-bandwidth product

Abstract

Flat band slow light with large bandwidth and low GVD in a novel PC waveguide is investigated. By using only one tuning parameter with respect to a simple W1 waveguide, unusual U type ng-frequency curves are obtained, enabling a versatile control of light group index and bandwidth. Delay-bandwidth products have been estimated for the proposed waveguide geometry (0.1363 for ng = 211 < DPBs < 0.336 for ng=11) and can be faborably compared with values reported in previous works. The GVD properties of the proposed structure have been also analyzed. It turns out that nearly-zero dispersion waveguiding can be achieved within the constant high ng range. Addtionnaly, the new waveguide allows a versatile control of positive or negative GVD values, opening opportunities for dispersion compensation devices. Finally, the novel simple PC waveguide is relatively easy for fabrication if compared with previously proposed solutions. Possible applications of the proposed δx PC waveguides can be found in optical interconnects, nonlinear optics, or biophotonics.