Light is guided from a light source into a waveguide coupler embedded in a slider. The light source is capable of being positioned in a cross-track, a down-track, and a vertical direction with regards to the waveguide coupler. The light emanating from an air-bearing surface of the slider is imaged using a device that generates an optical image of the air-bearing surface. A cross-track alignment position is identified as a location at which the image shows substantially the same number of photons on each side of the cross-track alignment position and has a minimum spread. A down-track alignment position is identified at which the light emanating from the air-bearing surface has maximal intensity in a down-track direction.