Photoconductive sampling probe with 2.3-ps temporal resolution and 4-μV sensitivity

Abstract

We report on a novel probe technology which is applied to the measurement of high-speed guided electrical signals. The probe consists of a high-impedance gate fabricated using an interdigitated electrode structure on semi-insulating, low-temperature-grown GaAs, and its operation is based on the optoelectronic technique of photoconductive sampling. The probe has a dynamic range of ≳106, permitting the linear measurement of short-duration signals with amplitudes ranging from microvolts up to several volts. Its resistance is 100 MΩ, and its capacitance is less than 0.1 fF, making this probe attractive for noninvasive, external circuit testing of ultrahigh-speed devices and circuits.