A new type of wideband slow light with a large delay bandwidth product in a slab photonic crystal waveguide with a triangular lattice of circular air holes in a silicon-on-insulator substrate based on optofluidic
infiltration is demonstrated. It is shown that dispersion engineering through infiltrating optical fluids—
with different refractive indices n1f and n2f —in the first two rows of the air holes innermost to the waveguide results in an improved normalized delay bandwidth product ranging from 0.187 to 0.377 with large
bandwidth 12 nm < Δλ < 32 nm and group index 14.20 < ng < 24.62 around 1550 nm. The nearly
zero group velocity dispersion on the order of 10−20 s2∕m is achieved in all of the structures. These
results are obtained by numerical simulation based on a three-dimensional-plane-wave expansion
method. © 2015 Optical Society of America
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