Two-dimensional photonic crystal hexagonal waveguide ring laser

Hexagonal ring-type resonators defined by two-dimensional photonic crystal waveguides are proposed and demonstrated. Lasing actions are observed from the photonic crystal ring resonator patterned on a free-standing slab with InGaAsP active layers emitting near 1.55 μm. For a ring resonator with 8-μm diameter, the threshold peak pump power is ∼3 mW. The quality factor of the ring resonator mode estimated from below-threshold linewidth shows that the sum of the propagation loss and the bending loss of the photonic crystal ring resonator is less than ∼260 cm−1. The photonic crystal ring resonators can be used for the characterization of the optical losses in photonic crystal waveguides.