Excess noise measurement in avalanche photodiodes using a transimpedance amplifier front-end

We report a versatile system for measuring excess noise and multiplication in avalanche photodiodes, using a transimpedance amplifier front-end and based on phase-sensitive detection, which permits accurate measurement in the presence of a high dark current. The system, which we have used successfully on a wide variety of materials and device structures, can measure reliably the excess noise factor of devices with a capacitance of up to similar to 50 pF.