Fiber Bragg Grating Structures with Fused Tapers
Citation
Silva, S. F. O. , Ferreira, L. A. , Araújo, F. M. , Santos, J. L. and Frazão, O.(2011) 'Fiber Bragg Grating Structures with Fused Tapers', Fiber and Integrated Optics, 30: 1, 9 — 28.
Keywords
- fiber Bragg grating
- optical fiber sensors
- optical fiber tapers
- strain and temperature measurement
Brief
Fiber structures that combine abrupt tapers and fiber Bragg gratings (FBGs) can be used for strain and temperature measurement. One such structure is made by fabricating a taper in the fiber region with an FBG.Another structure is made by fabricating the taper first and then the FBG. The first device acts like a Fabry-Perot cavity, while the second acts like a phase-shifted Bragg grating.
Summary
This 2011 article in Fiber and Integrated Optics by Silva et al. examines fiber structures that combine abrupt tapers and fiber Bragg gratings (FBGs) for sensing applications.
Two main structures are explored:
- TFBG1: A taper is fabricated directly on an existing FBG. The taper effectively splits the grating, creating a Fabry-Pérot interferometer.
- TFBG2: An FBG is written on a fiber that already has a taper. This alters the grating's effective refractive index, resulting in a phase-shifted FBG.
- Both TFBG1 and TFBG2 structures demonstrate potential for strain and temperature sensing. The study found:
- Strain Sensitivity: Both structures show measurable strain responses, although lower than standard FBGs, likely due to stress concentration at the reduced diameter of the taper.
- Temperature Sensitivity: Both structures exhibit temperature sensitivities comparable to uniform FBGs.
- Simultaneous Measurement: The structures' spectral responses allow for the potential of simultaneous strain and temperature measurement.
The authors conclude that these FBG structures with fused tapers show promise for sensing applications, particularly for simultaneous measurement of strain and temperature.