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

Abstract

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 temperature, ultrahigh gain ( $M=278$ , $\lambda =1550\mathrm{n}\mathrm{m}$ , $V=69.5\mathrm{V}$ , $T=296\mathrm{K}$ ) linear mode APD on an InP substrate using a ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}}_{0.5}{\mathrm{S}\mathrm{b}}_{0.5}/{\mathrm{A}\mathrm{l}}_{0.85}{\mathrm{G}\mathrm{a}}_{0.15}{\mathrm{A}\mathrm{s}}_{0.56}{\mathrm{S}\mathrm{b}}_{0.44}$ separate absorption, charge, and multiplication (SACM) heterostructure. This represents $\sim 10\times$ gain improvement ( $M=278$ ) over commercial, state-of-the-art InGaAs/InP-based APDs ( $M\sim 30$ ) 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 temperature breakdown sensitivity ( $C_{\mathrm{b}\mathrm{d}}$ ) of $\sim 11.83\mathrm{m}\mathrm{V}/\mathrm{K}$ , which is $\sim 10\times$ 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.