Method for detecting defects in fibers
US5185636A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1991 |
| Grant date | Feb 9, 1993 |
| Priority date | — |
| Expiry date | Dec 31, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods for deteting defects, such as, holes or voids, in optical waveguide fibers are provided. The methods employ far-field interference patterns produced by transversely illuminating the fiber with a laser beam. Holes in the fiber produce a characteristic peak in the spatial frequency spectrum of the interference pattern which subdivides into two peaks which migrate in opposite directions as a hole grows in size. Holes also produce a characteristic increase in the total power of the interference pattern, the amount of the increase being a linear function of the size of the hole for holes having a diameter less than about 60% of the diameter of the fiber. The hole detection methods are incorporated in an overall system for controlling the drawing of optical waveguide fibers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.