A dispersion compensator using coupled defects in a photonic crystal

We propose a new type of dispersion compensator that uses the characteristics of light traveling in a coupled defect waveguide (CDW) in a photonic crystal. By using a theoretical computation based on the plane-wave method, we show that the CDW band appears within the bandgap and its characteristics are well reproduced by the tight-binding (TB) model. We calculate the wavelength dispersion of light propagating in the CDW using TB formalism. The calculated result shows an inherently large dispersion of the CDW, which enables the realization of an extremely small dispersion compensator of a few tens of millimeters in size.