Abstract: An optical emission device includes a laser source having an emitting surface, and a sensor laterally adjacent the laser source generating an output signal dependent on the amount of light falling on its detection surface. A transparent waveguide is located in front of the emitting surface and extends generally parallel thereto such that light striking the waveguide in a direction normal to the emitting surface passes straight through the waveguide. A coupling medium is placed between the emitting surface and the waveguide. A light dispersant in the coupling medium causes a fraction of the laser light to strike the waveguide at an oblique angle so that it can enter the waveguide and be carried thereby to the sensor. An important advantage of the invention is that is uses inexpensive passive parts. The assembly process easy to implement, and the parts are stable during temperature changes. As a result only a small tracking error occurs.