Abstract
The light source position dependence of the evanescent wave coupling effect in a sub-wavelength-sized GaAs/AlGaAs ridge structure was investigated using the theoretical simulation and temperature-dependent emission pattern measurements. It was found that the evanescent wave coupling effect could be realized for a light source located at any position of the top-flat quantum well (QWL), although the emissions transformed from evanescent waves began to get emitted in directions that formed an increasingly larger angle with respect to the surface normal of the ridge flat facet when the light source was moved from the center to the edge of the flat QWL.