240-GHz Gain-Bandwidth Product Back-Side Illuminated AlInAs Avalanche Photodiodes

We demonstrate an AlInAs/InGaAs SAGM APD with a very thin avalanche layer operating at 1550nm for 10Gb/s optical transmission achieving simultaneously high responsivity (0.9 A/W at M = 1), very low excess noise factor (F(M=10) = 3) and very high gain-bandwidth product of 240GHz. To our knowledge, this is the first time that a back-side illuminated planar junction AlInAs/InGaAs APD achieve such performances.