Feature

External electro-optic sampling

J. Valdmanis, S. Pei, and M. Nuss

Scientists at Bell Laboratories have developed and demonstrated a new, non-contact, picosecond, electro-optic technique for obtaining signal waveforms at internal nodes of high speed integrated circuits or from discrete devices fabricated on any substrate material.1 This technique, referred to as external electro-optic sampling, achieves sub-picosecond temporal resolution with a spatial resolution of a few microns. It is designed to operate at the wafer level on conventional wafer probing equipment without any special circuit preparation. Initial experiments have characterized GaAs SDHT prescaler circuits, and also addressed the inherent speed and loading limits of the technique. Temporal resolution of less than 300 fs has been shown.