A proximity sensor may include an array of Geiger mode avalanche photodiodes, each including an anode contact and a cathode contact. A common cathode contact may be coupled to the cathode contacts of the array to define a first connection lead at a back side of the array. A common anode collecting grid contact may be coupled to the anode contacts of the array to define a second connection lead of the array. Circuitry may be coupled with the first and second connection leads and configured to sense at least one of a dark current and a rate of current spikes generated in dark conditions, and generate an output signal representing an estimated distance of an object from the array upon the sensing.