Highly sensitive optical fiber cavity coating removal detection
US5493113A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1994 |
| Grant date | Feb 20, 1996 |
| Priority date | — |
| Expiry date | Nov 29, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/45
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A highly sensitive optical fiber cavity coating removal detector employs an optical fiber 18 having a pair of Bragg gratings 20,30 embedded therein and separated by a section of fiber making up an optical cavity 26. The optical path length of the cavity 26 is sized with the central reflection wavelength of the fiber gratings 20,30 so as to create an optical resonator. The cavity 26 is coated with a material 40 which corrodes or is otherwise removable, such as aluminum. The coating 40 exerts forces 46 radially inward on the cavity 26 so as to cause the refractive index of the cavity and thus its optical path length to change, thereby causing the resonator to come out of resonance. The forces 46 on the cavity 26 are reduced when the coating 40 corrodes, thereby causing the resonator to re-enter resonance. Additionally, the coating causes optical losses to exist due to non-uniform variations in refractive index caused by non-uniform forces from coating irregularities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.