Issues when designing hypoellipse photonic crystal waveguides

This work designs a type of line-defect photonic crystal waveguide (PCW) called hypoellipse PCW (HPCW) that considers two conflicting issues: group index and bandwidth. To do so, the recent multi objective framework called MoMIR is employed. A wide range of designs obtained demonstrates the advantage of considering group index and bandwidth simultaneously when designing HPCWs. Comparison of the proposed HPCW with the current best PCWs shows a nearly 7% improvement over the latter in terms of normalized delay-bandwidth product (NDBP). Analysis of the results reveals some of the physical rules about the structure of the HPCW. Finally, optical pulse propagation in obtained HPCWs and the process of designing an optical buffer by using an obtained design are explained.