<p> </p>
<p>An extremely low noise Separate Absorption and Multiplication Avalanche Photodiode (SAM-APD), consisting of a GaAs<sub>0.52</sub>Sb<sub>0.48</sub> absorption region and an Al<sub>0.85</sub>Ga<sub>0.15</sub>As<sub>0.56</sub>Sb<sub>0.44</sub> avalanche region, is reported. The device incorporated an appropriate doping profile to suppress tunnelling current from the absorption region, achieving a large avalanche gain, ~130 at room temperature. It exhibited extremely low excess noise factors, of 1.52 and 2.48 at the gain of 10 and 20, respectively. At the gain of 20, our measured excess noise factor of 2.48 is more than 3 times lower than that in the commercial InGaAs/InP SAM-APD. These results were corroborated by a Simple Monte Carlo simulation. Our results demonstrated the potential of low excess noise performance from GaAs<sub>0.52</sub>Sb<sub>0.48</sub>/ Al<sub>0.85</sub>Ga<sub>0.15</sub>As<sub>0.56</sub>Sb<sub>0.44</sub> avalanche photodiodes.</p>
Funding
UK-Engineering and Physical Sciences Research Council grants (EP/N020715/1 and EP/K001469/1)