Two-dimensional photonic crystal couplers for unidirectional light output

We investigate the use of two-dimensional photonic crystal slabs to improve the directionality of output coupling from planar waveguides and distribut ed-feedback lasers. We present the theory underlying the operation of such structures and design criteria for emission in desired directions. As an ex ample, we demonstrate a vertical coupler that is integrated with an organic distributed-feedback laser, use computer simulations to find its coupling constant and efficiency, and then discuss its feasibility. (C) 2000 Optical Society of America.