High-speed, high-responsivity, and high-power performance of near-ballistic uni-traveling-carrier photodiode at 1.55-/spl mu/m wavelength

We demonstrate a novel photodiode at a 1.55-μm wavelength: the near-ballistic uni-traveling-carrier photodiode (UTC-PD). After a p/sup +/ delta-doped layer was inserted into the collector of a UTC-PD, near-ballistic transport of photogenerated electrons under high reverse bias voltage (-5 V) and a high output photocurrent (/spl sim/30 mA) was observed. The demonstrated device has been combined with an evanescently coupled optical waveguide to attain high responsivity and high saturation power performance. Extremely high responsivity (1.14 A/W), a high electrical bandwidth (around 40 GHz), and a high saturation current-bandwidth product (over 1280 mA/spl middot/GHz, at 40 GHz) with high saturation radio-frequency power (over 12 dBm at 40 GHz) have been achieved simultaneously at a 1.55-μm wavelength.