Optical Crosstalk in InGaAs/InP SPAD Array: Analysis and Reduction With FIB-Etched Trenches

This letter describes the reduction of optical crosstalk by means of focused ion beam-etched trenches in InGaAs/InP single-photon avalanche diode arrays. Platinum-filled trenches have been fabricated in a linear array in order to limit the direct optical crosstalk between neighboring pixels. Experimental measurements prove that optical crosstalk has been reduced by ~60% thanks to a strong suppression of direct optical paths. An optical model is introduced in order to describe the main contributions to crosstalk and to validate measurements.