An efficient waveguide photodetector fabricated in an InP-based amplifier layer stack

This article describes the fabrication and characterization of a waveguide pin-photodetector\u3cbr/\u3e(WGPD) based on butt-joint integration of a passive waveguide and photodetector.\u3cbr/\u3eThe WGPD is fabricated in a layer stack that is designed to be used for an optical amplifier,\u3cbr/\u3ewhich now acts as a detector by reversely biasing the pin-diode. The device is\u3cbr/\u3efabricated in active-passive material with a technology that uses two epitaxial regrowth\u3cbr/\u3esteps. The static and high-frequency behavior of the photodetector are characterized and\u3cbr/\u3edemonstrate a very low dark current of 20 nA at -4 V and an internal efficiency of more\u3cbr/\u3ethan 65% for a 60μm long device at -5V bias voltage around a wavelength of 1.5μm. The\u3cbr/\u3eoutput reflection coefficient shows more than 20GHz bandwidth for a 70μm long device