High gain, low noise 1550 nm GaAsSb/AlGaAsSb avalanche photodiodes

High sensitivity avalanche photodiodes (APDs) operating at eye-safe infrared wavelengths (1400-1650 nm) are essential components in many communications and sensing systems. We report the demonstration of a room tem-perature, ultrahigh gain (M = 278, lambda = 1550 nm, V = 69.5 V, T = 296 K) linear mode APD on an InP substrate using a GaAs0.5Sb0.5/Al0.85Ga0.15As0.56Sb0.44 separate absorption, charge, and multiplication (SACM) heterostructure. This represents similar to 10 x gain improvement (M = 278) over commercial, state-of-the-art InGaAs/InP-based APDs (M similar to 30) operating at 1550 nm. The excess noise factor is extremely low (F < 3) at M = 70, which is even lower than Si APDs. This design gives a quantum efficiency of 5935.3% at maximum gain. This SACM APD also shows an extremely low tem-perature breakdown sensitivity (C-bd) of similar to 11.83 mV/K, which is similar to 10x lower than equivalent InGaAs/InP commercial APDs. These major improvements in APD performance are likely to lead to their wide adoption in many photon-starved applications.