Method and apparatus for measuring internal index of refraction of preform of optical fiber
US6919954B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jun 12, 2001 |
| Grant date | Jul 19, 2005 |
| Priority date | — |
| Expiry date | Jun 12, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/088
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method and system for measuring the internal refractive index of an optical fiber preform with high precision. The internal refractive index of an optical fiber preform (2) is measured from the state of bending of a light ray (4) passing across the optical fiber preform (2), so that the refractive index distribution of the optical fiber preform (2) is found on the basis of the angle of bending of the light ray calculated from a specific relation between a light ray start position (8) and a light ray detection position (9). The surface of a light source (1) is scanned by a knife-edge (6) and the light ray start position (8) on the light source is determined depending on the interception of the light ray (4) by the knife-edge (6) or the de-interception of the light ray, thereby learning the start position (8) of the detected light ray (4) on the light source (1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.