Bias-free selectively doped AlxGa1−x As-GaAs picosecond photodetectors

Abstract

We demonstrate a novel Al_xGa_1−x As‐GaAs picosecond photodetector which does not require any bias voltage. High‐speed operation is achieved by an inherent capacitive coupling, a unique microwave mounting scheme, and a selectively doped structure. An observed rise time of 30 ps and a full width at half‐maximum of 60 ps have been reproducibly obtained for a device with an area two orders of magnitude larger than a previously reported device. This detector enables monolithic integration with modulation‐doped field‐effect transistors. Furthermore, the results point to a possibility of achieving a bias‐free detector for a gigabit‐rate optical communication system.