Abstract

Despite the success of external electro-optic (EO) probing in measuring ultrafast time-domain signals with an extremely large bandwidth [1], issues involving the invasiveness of the probe, the repeatability of the measured results, the ability to measure low-frequencies, and the calibration of voltage signals have served to impede the impact of EO sampling on high-speed-device and circuit testing. The main problem associated with the external probe is the high permittivity of the EO material used (e.g., lithium tantalate has a relative permittivity which is as high as 44). This probe not only creates an impedance mismatch and reflections, but it also renders the measurement results somewhat unreliable by preferentially excluding electric fields of certain frequencies depending on the height of the probe, h, with respect to the circuit under test.

© 1995 Optical Society of America