Fiber optic sensor arrangement having reflective gratings responsive to particular wavelengths
US4950883A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 27, 1988 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Dec 27, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/29356
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An arrangement for sensing changes in a monitored parameter includes an optical fiber which has at least one sensing fiber length including a sensing portion situated at a monitoring location of a body. Two periodic gratings of the same periodicity are situated in the fiber each at a different end of the sensing fiber length. Such gratings are reflective to a predominant portion of any light that propagates in the fiber and has a wavelength in a stopband range around twice the periodicity. When broadband coherent light including sensing light with wavelengths within the stopband range is launched into a first end of the optical fiber for propagation longitudinally of the fiber toward a first of the gratings, the predominant portion of the sensing light is reflected from the first grating and the remainder of the sensing light passes into the sensing fiber length, where resonant buildup of light at certain wavelengths that are located within the stopband range and depend on the length of the sensing portion as influenced by changes in the monitored parameter takes place, and the gratings are rendered substantially transparent to the sensing light at the plurality of wavelengths foll…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.