Abstract
At least two Fresnel lenses are formed on a transparent substrate, and a set of parallel plates are established in an acute included angle (from 19.degree. to 90.degree.) with the transparent substrate by an inclined exposure process employing a thick film photoresist. The parallel plates are separately placed over the Fresnel lenses. Metal layers are separately deposited on the outside surfaces of the parallel plates far from the acute included angle. A transparent polymeric material is overlaid on the surface of the transparent substrate till the parallel plates are immersed. An objective lens, placed over a photo detector, is formed on the surface of the transparent polymeric material. A laser diode is placed at a location on the surface of the substrate opposite to one of the Fresnel lenses, and the photo detector is placed at a location on the surface of that opposite to another of the Fresnel lenses.