Custom Fiber Bragg Grating Array Fabrication Through Any Polymer Coating of Optical Fiber With Any Core Material
Sentek Instrument fiber Bragg gratings demonstrate exceptional thermal stability, even at temperatures exceeding 300°C. Our state-of-the-art gratings offer several major benefits for Rayleigh φ-OTDR or DAS interrogators. A proprietary manufacturing technique yields ultrahigh-quality broadband FBGs in any fiber, including pure silica core fiber with various coating options. The quality of each FBG is continuously monitored during fabrication to ensure uniform optical power reflection within tight tolerances. Precise control over fiber and upstream grating loss compensation is maintained at an individual grating level. Customers can request broadband reflectance-weighted gratings with either constant or varying spacing. Moreover, a fiber can incorporate multiple grating zones, each containing numerous FBGs, and these zones can be arranged according to the customer’s requirements.
Key Advantages of Sentek FBGs
- Significant sensitivity enhancement
- Suppression of random sensitivity fluctuations across fiber segments and over time
- Large bandwidth
- Customer-specified varying grating reflectivities with individual grating tailorability and their distributions along the fiber
- Excellent thermal stability
- Precision grating spacing control
Ideal For
- DAS sensitivity boost
- In-line fiber devices
Technical Specifications
Details
| FBG Reflecting Strength | -40 to -55dB |
| 3dB Bandwidth | >20nm |
| Grating Spacing | 1m to 50m, or custom |
| Grating Spacing Precision | ±2mm or 0.2% of spacing, whichever gives greater uncertainty |
| Grating Reflectance Distribution | Uniform reflectance or uniform reflected power |
| Standard Deviation of Reflected Powers | 0.5dB typical |
| Fiber Types | Pure silica core fiber, telecom fiber such as SMF-28 |
| Fiber Coatings | Standard and high-temperature acrylate, polyimide |
| Grating Zone Partition Options | Any |
| Maximum Fiber Length | 10km, actual max length dependent on grating quantity and reflectance |
OTDR trace showing 1,065 serial broadband fiber Bragg gratings. These gratings offer constant optical power at the photodetector on the fiber input end. The original fiber coating is preserved, maintaining high tensile strength of the grating array.
The graph shows the uniformity of the detected relative powers for 4 grating arrays. Each grating array has more than 1,000 FBGs with 4,160 gratings total.
OTDR measurement of an FBG array with reflectors spaced every 5m over 5,065m. The average reflectivity has no intrinsic degradation with distance, with a measured start-to-end decrease of approximately 0.2dB. The reflectivity has very little grating-to-grating variation.