Extremely low noise InAs and AlGaAsSb avalanche photodiodes for low photon detection in infrared wavelengths

There is an increased demand for low noise avalanche photodiodes (APDs) for infrared wavelengths at 1550 nm for long range Light Detection and Ranging applications. Here we present two classes of APD that produce high avalanche gain but with extremely low excess noise factors, F ~ 2. InAs APDs show F < 2 and offer detection wavelength up to 3500 nm, although this drops to ~3000 nm when cooled. For reducing effects of scattering in atmosphere, InAs could be an attractive option. In addition InAs APDs are based on a simple homojunction design, which is relatively easy to grow epitaxially. AlGaAsSb when combined with InGaAs, provides a direct replacement for the traditional InGaAs/InP APDs. It is therefore capable of room temperature performance with excess noise performance similar to Si APDs but operates at 1550 nm. We will present results that show noise equivalent power as low as 69 fW/Hz0.5.