Dispersion compensation based on the combination of coupled ring resonator and photonic crystal structures

An optical delay line of coupled resonator optical waveguide (CROW) compensated by photonic crystal waveguide (PhCW) is proposed. In the structure, etching the periodic holes around the waveguide of the ring resonator waveguide does not increase the size of the CROW. Theoretical studies and numerical models indicate that through careful design, CROW and PhCW exhibit different group velocity dispersion (GVD) properties at a certain frequency range. Optical signal can not only be compensated in terms of GVD, but can also be delayed with longer time period. Due to the propagation mode mismatch of the two structures, optical loss becomes inevitable.