100 GHz long wavelength low capacitance waveguide InGaAs/InP p-i-n photodiode with multimode waveguide structure

We describe a 100 GHz waveguide InGaAs/InP p-i-n photodiode based on multimode waveguide structure. The measured background carrier concentration in the unintentionally doped In0.53Ga0.47As absorption layer is as low as similar to 10(15) cm(-3), and the capacitance of the device is 32 fF at a -1.0-V bias voltage, including the parasitic capacitance of the bonding pad. This measured capacitance confirms the RC time limited bandwidth of 100 GHz in this fabricated multimode waveguide photodiode. The waveguide photodiode has an extremely low leakage current of a few nA at -1-V bias voltage, high responsivity of 0.58 A/W, and 1-dB-down misalignment tolerance of 2.0 and 5.0 mum in the vertical and horizontal directions, respectively. The multimode waveguide structure is adequate for monolithic integration with a Microwave Monolithic Integrated Circuit (MMIC), such as amplifier circuits, due to a single epitaxial growth step on a Heterojunction Bipolar Transistor (HBT) epitaxial wafer structure.