Electro-optic signal measurement
US4873485A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 13, 1988 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Jul 13, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R1/071
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Direct voltage measurements of electrical signals are extracted from transmission lines for display in a manner to permit such measurements with picosecond temporal and submicron spatial resolution utilizing a noncontacting electro-optic probe. The probe may have multiple quantum well (MQW) structure. The NQW structure defines an active region sufficiently small (less than a micron if desired) in width so that it can be placed between neighboring lines on an integrated circuit. A short pulse laser beam is used to sense the absorption change at the time window of interest. The electroabsorption effect in the MQW structure is a nonlinear function of the strength of the electric field. Detection can be carried out by sampling techniques to provide the measurement of the voltage or the display of the signal. Problems arising from crosstalk from neighboring conductors or elements and the lack of bipolar response of the electroabsorption effect have been solved using a reference electrode on one side of the MQW structure to which a voltage is applied for developing a field that cancels the field due to the signal being measured, thereby providing a voltage signal corresponding both in am…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.