Abstract: An integrated optical waveguide coupler for coupling energy in one direction to illuminate an optical stylus tip and for carrying energy received by said tip in the opposite direction to a remote transducer. The integrated coupler includes a substrate comprising a first relatively low refractive index material having a face and a second relatively high refractive index material formed on said face, as a right angle prism. A low refractive index layer of predetermined thickness is interposed between said substrate and the optical waveguide. Light energy incident to a surface of the prism is coupled to the waveguide.