Antisymmetric Grating Coupler: Experimental Results

The principle of an antisymmetric grating coupler was recently proposed theoretically as a planar waveguide add-drop multiplexer. It has the potential to enhance significantly the functionality of an add-drop multiplexer based on grating-assisted coupling. Here we realize the concept experimentally in an all-fiber geometry. We show that conventional devices exhibit two high-reflection bands. In contrast, the antisymmetric grating coupler has only a single reflection band, thereby dramatically improving its filtering characteristics.