Optical probing method and apparatus
US5126661A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1990 |
| Grant date | Jun 30, 1992 |
| Priority date | — |
| Expiry date | Oct 18, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/308
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An integrated circuit (11) is tested at a high microwave frequency through the use of a laser beam (19) having a repetition rate much lower than the test frequency. Electric fields of the test signal extend into an electro-optic material (12) that modulates part of the laser beam. Another part of the laser beam is converted to an electrical pulsed signal that is applied to a microwave mixer (33) along with part of the test frequency signal. A harmonic of the pulsed signal mixes with the test frequency to yield a difference frequency that can be used as a phase reference for analyzing the phase of the test signal. The component pulses (30) of the laser beam have a pulse width which is much shorter than the separation of the pulses, which make it inherently rich in higher harmonics of the fundamental pulse repetition rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.