Abstract

In this work, high-speed 850 nm GaAs/AlGaAs based dual-depletion-region photodetectors are demonstrated, which aim to meet the increasing need for bandwidth scaling and data rate in short-reach optical links. The devices exhibit the low dark current of ∼134.5 fA and responsivity of ∼0.44 A/W at 850 nm. The 3-dB bandwidth of 20 μm and 28 μm diameter devices with 50-ohm characteristic impedance transmission line were measured to be 29.72 GHz and 24.71 GHz respectively. While by incorporating inductive peaking via high characteristic impedance transmission line, the 20 μm and 28 μm diameter devices achieved maximum 3-dB bandwidth of 46.06 GHz and 36.09 GHz respectively. To the best of our knowledge, this 20 μm diameter device exhibits the highest 3-dB bandwidth among all the 850 nm photodetectors. This research showcases the potential of 850 nm dual-depletion-region photodetectors as promising solutions for high-speed short-reach optical communication systems, offering improved performance in terms of bandwidth and enabling the advancement of data transmission capabilities.