Crosstalk analysis in large-area low-capacitance InGaAs quad photodiodes

Abstract

We report crosstalk in 1 mm diameter and 2 mm diameter quad InGaAs photodiodes having quadrant-to-quadrant separation of 15 μm, 20 μm, and 25 μm. This crosstalk is a combination of resistive and capacitive coupling between the photodiode quadrants and varies widely on the combination on device diameter, quadrant-to-quadrant separation, illumination conditions, and modulation frequency. Thus, the position sensing accuracy is heavily influenced by the operating conditions of the quad photodiode.