High speed and high responsivity dual-absorption InGaAs/InP UTC-PDs

A new back-illuminated uni-traveling-carrier photodiode (UTC-PD) is designed for long-wavelength applications in this paper. This device design incorporates dual absorption regions with conventional UTC-PDs, simultaneously by adopting a cliff layer in the collection layer to obtain high efficiency and high speed. Theoretical and simulation study indicate that the responsivity of the 14 μm² active area device is as high as 0.33 A/W, and a 3-dB bandwidth up to 52.2 GHz at 2V reverse bias. This represents an improvement of 70% over the bandwidth-responsivity product achievable in conventional back-illuminated uni-traveling-carrier photodiode.