Abstract

Since its introduction [1], electrooptic (EO) sampling has rapidly developed as a tool for ultrafast electrical measurements [2], [3] with temporal resolution extending to less than a picosecond. The basic physical phenomenon underlying this technique, the Pockels effect, is well-described in the literature [1-5]. The work reported here relies on the fact that GaAs, the substrate material for many high-speed circuits, is electrooptic. Using a longitudinal probing geometry [4], [5], sub-bandgap energy infrared light is passed through the substrate of GaAs integrated circuits (IC's), reflected off some circuit metallization, and passed through a polarizer, resulting in an intensity change of the light proportional to the voltage across the substrate. In addition, the signal generating electronics for driving the IC's are phase locked to the repetition rate of a mode-locked laser laser, allowing sampled measurements of voltage waveforms due to sinusoidal excitation of the circuit. Figure 1 shows the system schematic.

© 1986 Optical Society of America