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Electrical and electronic engineering
The strain and temperature dependencies of a step-index single-mode–multimode–single-mode (SMS) fiber structure are investigated numerically and experimentally. For intensity-based strain measurement using a single SMS fiber structure, at a selected wavelength, it is found that there is a high strain dependence, but also a temperature dependence that will induce strain measurement error. To minimize the temperature-induced strain measurement error, two SMS fiber structures are proposed and demonstrated in a ratiometric power measurement scheme; one SMS structure acts as the strain sensor, and the other SMS structure acts as the temperature monitor. The extracted temperature information is used to determine a strain value based on a suitable calibration of strain responses with temperature variations. It is demonstrated that for strain measurement from 0 to 1000 με within the temperature range from 10°C to 40°C, the proposed configuration can provide a strain and temperature resolution of 0:34 με and 0:14°C, respectively, with a temperature-induced strain measurement error as low as 0:39 με.
Hatta, A. et al. (2010) Strain Sensor Based on a Pair of Single-Mode-Multimode-Single-Mode Fiber Structures in a Ratiometric Power Measurement Scheme. Applied Optics. Vol.49, no.3. doi:10.1364/AO.49.000536