Why are the majority of FBG sensors fabricated on single-mode fibers?
FBG sensors are predominantly fabricated on single-mode fibers due to several critical technical advantages:
- Stable Mode Propagation: Single-mode fibers (SMF) guide light in a single, well-defined optical mode. This ensures that the light interacting with the Fiber Bragg Grating (FBG) has a consistent and predictable wavefront, leading to a sharp and distinct reflection spectrum. In contrast, multi-mode fibers support multiple propagation modes, which can lead to modal dispersion and a broadened, less precise FBG spectrum, making accurate sensing challenging.
- Efficient Grating Interaction: The stable mode in SMF allows for highly efficient and localized interaction with the periodic refractive index modulation of the FBG. This maximizes the reflectivity at the Bragg wavelength, producing strong and clear signals.
- Accuracy and Precision: The well-defined spectral response from FBGs in single-mode fibers translates directly into higher accuracy and precision in measurement for various parameters like strain and temperature. Any shifts in the Bragg wavelength, indicative of changes in the measured physical quantity, can be detected with greater resolution.
- Compatibility with Standard Telecommunication Infrastructure: Many FBG applications benefit from compatibility with existing single-mode fiber optic communication infrastructure, simplifying deployment and integration.
For instance, OFSCN® Polyacrylate Fiber Bragg Gratings / Fiber Bragg Grating Strings (bare) are typically fabricated using standard single-mode G.652D optical fiber to ensure optimal performance.
Here is an example of an FBG sensor:
You can find more information about our bare Fiber Bragg Gratings here:
OFSCN® Polyacrylate Fiber Bragg Gratings / Fiber Bragg Grating Strings (bare)
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