Apparatus for coupling an optical fiber to a structure at a desired angle
US5448662A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1993 |
| Grant date | Sep 5, 1995 |
| Priority date | — |
| Expiry date | Feb 24, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B5/0014
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Optical metrology apparatus, specifically a laser probe (1), includes a frame (10) comprised of a material selected to have a predetermined coefficient of thermal expansion. A beamsplitter (36) is coupled to the frame for generating a sample beam optical path (D) and a reference beam optical path (C). The beamsplitter is optically coupled to an optical fiber (12) that delivers radiation to and conveys radiation from the frame. A piezoelectric stack (48) has an excitation signal coupled thereto and includes a mirror (26) for phase modulating the reference beam optical path length in response to the excitation signal. The laser probe includes a first strain gauge (58) that is coupled to the piezoelectric stack and a second strain gauge (60) that is coupled to the frame. A closed loop control system (A1, A2, A3, A4, VR) varies the excitation signal in accordance with the detected strains so as to maintain the reference beam optical path length in a predetermined relationship to a path length of the sample beam optical path. This athermalizes the probe, in that any expansion or contraction of the frame is matched by the piezoelectric stack, yielding a net zero change in the non-common …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.