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Adaptable Optical Fiber Displacement-Curvature Sensor Based on a Modal Michelson Interferometer with a Tapered Single
G Salceda-Delgado1, A Martinez-Rios2, R Selvas-Aguilar3
1Universidad Autónoma de Nuevo León, Pedro de Alba S/N, Ciudad Universitaria, 66455 San Nicolás de los Garza, Nuevo León, Mexico. guillermo.salcedadl@uanl.edu.mx.
Sensors (Basel, Switzerland)
|June 3, 2017
Summary
A novel optical fiber sensor accurately measures displacement and curvature. By bending a specialized fiber taper, changes in light interference patterns reveal precise measurements, offering high sensitivity for various applications.
Area of Science:
- Optoelectronics
- Fiber Optics
- Sensor Technology
Background:
- Optical fiber sensors offer non-intrusive measurement capabilities.
- Modal interference in optical fibers can be exploited for sensing applications.
Purpose of the Study:
- To present a compact and highly sensitive optical fiber sensor for displacement and curvature radius measurement.
- To investigate the sensing mechanism based on modal coupling and interference in a fused fiber taper.
Main Methods:
- Fabrication of a sensor head comprising an adiabatic bi-conical fused fiber taper spliced to a single-mode fiber (SMF) segment.
- Inducing axial displacement to bend the fiber taper, causing asymmetry and loss of adiabaticity.
- Analyzing the resulting interference patterns in the reflection spectrum, including fringe visibility and wavelength shifts.
Main Results:
- The bent bi-conical taper induces modal interference, producing a periodical reflection spectrum.
- Changes in fringe visibility and wavelength shifts correlate with applied displacement and bending.
- Achieved displacement sensitivities ranging from 1.93 to 3.4 nm/mm with varying SMF lengths (7.5-12.5 cm).
Conclusions:
- The developed optical fiber sensor effectively measures displacement and curvature radius.
- Both wavelength shift and visibility contrast interrogations provide reliable measurement data.
- The sensor's sensitivity is tunable via the selection of the SMF length, demonstrating its versatility.
