We demonstrate uni-directional evanescent coupling of lasing emission from awavelength-scale deformed microdisk to a waveguide. This is attributed to theGoos-H\"anchen shift and Fresnel filtering effect that result in a spatialseparation of the clockwise (CW) and counter-clockwise (CCW) propagating rayorbits. By placing the waveguide tangentially at different locations to thecavity boundary, we may selectively couple the CW (CCW) wave out, leaving theCCW (CW) wave inside the cavity, which also reduces the spatial hole burningeffect. The device geometry is optimized with a full-wave simulation tool, andthe lasing behavior and directional coupling are confirmed experimentally.
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