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