A BACK REFLECTION INSENSITIVE ELECTRO-OPTICAL INTERFACE AND A METHOD OF COUPLING THE SAME TO A WAVEGUIDE

An electro-optical interface with a package base (200) having an electrical connection configuration (202) suitable for connecting to a source of electrical signals. A semiconductor optical signal source (208) is provided mounted to the base (200) and having a second or higher order grating in the cavity. The signal source (208) is operatively connected to the package base (200) whereby the electronic signals may be converted into optical signals. A waveguide (216) is positioned adjacent to the signal source (208) to couple the optical signal to the waveguide (216). The cavity is sized, shaped and positioned so that a radiation field for the cavity is not a mode discrimination mechanism wherein any back reflections into the cavity will affect a coupling coefficient to the radiation field without significantly adversely affecting the output signal quality.