Strain Sensitivity Enhancement in Suspended Core Fiber Tapers

Citation

André, R. M., Silva, S. O., Becker, M., Schuster, K., Rothardt, M., Bartelt, H., ... & Frazão, O. (2013). Strain Sensitivity Enhancement in Suspended Core Fiber Tapers. Photonic Sensors, 3(2), 118–123).

• Optical fiber sensor
• taper
• microstructured fiber 

Brief

Tapered suspended core fibers have low temperature and external refractive index sensitivities, but they are extremely sensitive to strain. 

Summary 

This article focuses on increasing strain sensitivity in suspended core fiber (SCF) tapers. Researchers successfully created SCF tapers with diameters ranging from 70 μm to 120 μm using a filament heating method. The process involved proportionally reducing the core and cladding diameters while ensuring the holes within the structure did not collapse, even at significantly reduced sizes. This structural integrity allows for the transmission of light through an air-silica waveguide, minimizing interference from external factors like temperature changes or surrounding refractive indexes.

The study highlights a key finding: as the diameter of the taper decreases, its sensitivity to strain increases. For instance, a reduction in diameter from 120 μm to 80 μm resulted in a 64% increase in strain sensitivity. This sensitivity enhancement is attributed to the relationship between strain and the taper's cross-sectional area, as demonstrated by equations (1) - (8) in the article.

The research concludes that these SCF tapers demonstrate significant potential as sensing elements. They offer advantages over traditional fiber tapers, including increased strain sensitivity, minimal temperature sensitivity, and resilience against external environmental influences. These attributes make them promising candidates for applications requiring precise strain measurement.

Origin: https://link.springer.com/content/pdf/10.1007/s13320-012-0059-2.pdf