Distributed fiber optic temperature sensors and systems
First Claim
1. An optical fiber adapted to sense physical variables at different locations along its length, comprising at least two light-guiding regions A and B and so characterized that, when interrogated with light pulses of submicrosecond duration and of a wavelength or wavelengths within a suitable pre-selected spectral region injected into region A, the intensity of each interrogating light pulse propagating at each location along the fiber is distributed between said regions A and B, the relative distribution varying as a function of the magnitude of the physical variable acting on the fiber at that location, the fiber being adapted to automatically process said relative distribution into two resolvable optical signals the relative intensities of which are an indicator of said relative distribution, one of said two signals reaching at least one fiber end separated in the time domain from optical signals generated at other sensing locations along the fiber.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to fiber optic methods and devices for sensing physical parameters, like temperature or force, by converting a fraction of the intensity of the interrogating light into a positive signal with wavelengths and/or light propagation modes different from those of the interrogating light. Preferred embodiments make use of the redistribution of the intensity of the interrogating light between the core and a secong light-guiding region of an optical fiber probe, and the processing of the light carried by said second light-guiding region into a positive signal separable from the interrogating light.
-
Citations
16 Claims
- 1. An optical fiber adapted to sense physical variables at different locations along its length, comprising at least two light-guiding regions A and B and so characterized that, when interrogated with light pulses of submicrosecond duration and of a wavelength or wavelengths within a suitable pre-selected spectral region injected into region A, the intensity of each interrogating light pulse propagating at each location along the fiber is distributed between said regions A and B, the relative distribution varying as a function of the magnitude of the physical variable acting on the fiber at that location, the fiber being adapted to automatically process said relative distribution into two resolvable optical signals the relative intensities of which are an indicator of said relative distribution, one of said two signals reaching at least one fiber end separated in the time domain from optical signals generated at other sensing locations along the fiber.
Specification