Split-spectrum self-referenced fiber optic sensor
US5446280A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 31, 1993 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | Aug 31, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fiber optic sensor is fully compensated for light source intensity variation, fiber losses and modal power distribution by providing input to one end of an optical fiber from a relatively broad band light source containing at least two spectrally separated wavelengths. At least one of these spectrally separated wavelengths is reflected back into the optical fiber by a filter located between a second end of the optical fiber and a reflective transducer. The filter is preferably of the interference edge filter type and has a nominal cut-off wavelength within the spectral band of the light source or between the two spectrally separated wavelengths. Therefore, the paths traversed by light of the spectrally separated wavelengths will differ only by twice traversing the reflective transducer. Temperature measurement or compensation can also be provided by sensing of reflected light intensity or power at approximately the nominal cut-off frequency of the filter. Reflective transducers of both the intensity-based and interferometric types are usable with the invention.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.