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.