GaAs Integrated Circuit Testing Using Electrooptic Sampling

The principles of electrooptic sampling for high-speed testing of GaAs IC, its capabilities as both a time-domain sampling oscilloscope and a frequency-domain network analyzer, and recent measurements results are described. Applications of this system include measurements of internal-node switching signals and propagation delays in digital circuits with picosecond time resolution, small-signal and large-signal analysis of microwave circuits, and measurement of the one-port S-parameters on IC transmission lines to millimeter-wave frequencies. A method to measure two-port S-parameters using the optical probe is described. This technique defines an on-chip reference plane, reducing measurement errors and eliminating the calibration standards and routines required with conventional network analyzers.