The present invention is directed to a position sensing detector made of a photodiode having a semi insulating substrate layer; a buffered layer that is formed directly atop the semi-insulating substrate layer, an absorption layer that is formed directly atop the buffered layer substrate layer, a cap layer that is formed directly atop the absorption layer, a plurality of cathode electrodes electrically coupled to the buffered layer or directly to the cap layer, and at least one anode electrode electrically coupled to a p-type region in the cap layer. The position sensing detector has a photo-response non-uniformity of less than 2% and a position detection error of less than 10 μm across the active area.