Photonic crystal nanolaser monolithically integrated with passive waveguide for effective light extraction

We recently reported room-temperature continuous-wave operation in a GaInAsP photonic crystal slab nanolaser. In this letter, we demonstrate effective light extraction from the nanolaser monolithically integrated with a passive waveguide by using a GaInAsP butt-joint regrowth technique. Theoretically, the extraction efficiency through the waveguide was calculated to be 80% for the optimum design of the coupling system of the nanolaser and the waveguide. In the experiment, we evaluated a differential quantum efficiency of 4%, which was degraded mainly due to the detection loss of the output light.