High-Performance InP-Based Photodetector in an Amplifier Layer Stack on Semi-Insulating Substrate

A waveguide photodetector (PD) based on semi-insulating (SI) indium phosphide (InP) was simulated, designed, and fabricated. The layer stack for this PD was optimized for use as an optical amplifier or laser and it can be combined with the passive components. By using an SI substrate and deep etching, a small, efficient, and high-speed PD was made, which allows for easy integration of source, detector, and passive optical components on a single chip. A 3-dB bandwidth of 35 GHz and 0.25 A/W external radio-frequency reponsivity is measured at 1.55-mum wavelength for a 1.5-mum-wide and 30-mum-long waveguide PD at -4-V bias voltage. The polarization dependence in the responsivity is less than 0.27 dB.