Ultrawideband Low Dispersion Slow Light Waveguides

Abstract

In 2-D photonic crystals (PhCs), we demonstrate two novel line-defects slow light waveguides with little group velocity dispersion (less than 1 ps/nm/mm) in which light can propagate with little distortion in a wide frequency range. The first waveguide is composed of air rings located at the each side of the line-defect and the results indicate that a very flat band corresponding to average group velocity of 0.04 c can be achieved in the bandwidth of 4.9 THz. The second waveguide in which the high-index ridge waveguide is sandwiched between two photonic crystals may yield an average group velocity of 0.01777c over a bandwidth of 2.9 THz. Numerical simulations by finite-difference time domain (FDTD) verify the results of the frequency domain.