Zero-Dispersion Slow Light with Wide Bandwidth in Photonic Crystal Coupled Waveguides

By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide (W2) and the hole radii of the coupling region (r') will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity vg in incident waveguide can be achieved. In particular, proper W2 and r' can lead to the lowest vg of 0.0085c at 1550nm with wide bandwidth of 202GHz for zero dispersion.