Study of the properties of slow light in planar photonic crystal coupled-cavity waveguides

Characteristics of coupled-cavity photonic crystal waveguides are analyzed by plane-wave expansion method. By adjusting the radius of the dielectric rods, a linear band in the photonic band structure appears which denotes low group velocity dispersion. Based on the investigations and discussion of the flat band slow light mechanism in coupled-cavity photonic crystal waveguide, flat band low dispersion slow light in coupled-cavity photonic crystal waveguides formed by moving the dielectric rods nearest to the waveguide core is investigated. The waveguide structure with group velocity reduced to zero is demonstrated. Characters of group velocity dispersion (GVD) of slow light are also analyzed, and the magnitude of second-order coefficient of GVD value in the area of ultra slow light is about 10 5 ps 2 /km, which can guarantee the propagation with efficiency. The novel photonic crystal waveguide can provide various applications, such as optical delay line, optical buffering, all-optical storage and especially in enhanced light-matter interaction both in the linear and nonlinear regime.