Bend design for the low-group-velocity mode in photonic crystal-slab waveguides

We investigated bends for photonic crystals with triangular arrays of holes theoretically by employing two-dimensional band-structure and transmission calculations. We find that the guided mode of the bend is frequency-shifted compared with that of a straight waveguide. Decreasing the size of the holes in the immediate vicinity of the bend shifts the frequency of the mode back. These optimized bends can guide light in the frequency region of very low group velocities around comers. © 2004 American Institute of Physics.