Slow light property in ring-shape-hole slotted photonic crystal waveguide

Slow light in photonic crystal waveguide is now being heavily investigated for applications in optical devices. A ring-shape-hole slotted PhCW (RSPhCW) is designed in the paper. Band structures and group indices are calculated through plane wave expansion method. Flat band slow light property is observed, which provides low group velocity dispersion and avoids high speed optics signal from distortion in transmission. A method is proposed by tuning the positions of the first and second rows with the ring-shape-holes adjacent to the slot, which can tune the group index and the bandwidth of the guided band at the same time. This method is used to optimize the slow light property of the RSPhCW. The bandwidths ranging from 1.8 nm to 17.3 nm for group indices from 15 to 67 are obtained. From the point of view of reality, this method has its advantage of fabricating than tuning the outer and inner radii of the ring-shape-holes.