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Sensors 2010, 10(5), 4794-4804;

A Multi-D-Shaped Optical Fiber for Refractive Index Sensing

Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan
Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan
Department of Biomechatronics Engineering, National Pingtung University of Science and Technology, Pingtung 912, Taiwan
Authors to whom correspondence should be addressed.
Received: 10 March 2010 / Revised: 29 March 2010 / Accepted: 14 April 2010 / Published: 11 May 2010
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A novel class of multi-D-shaped optical fiber suited for refractive index measurements is presented. The multi-D-shaped optical fiber was constructed by forming several D-sections in a multimode optical fiber at localized regions with femtosecond laser pulses. The total number of D-shaped zones fabricated could range from three to seven. Each D-shaped zone covered a sensor volume of 100 μm depth, 250 μm width, and 1 mm length. The mean roughness of the core surface obtained by the AFM images was 231.7 nm, which is relatively smooth. Results of the tensile test indicated that the fibers have sufficient mechanical strength to resist damage from further processing. The multi-D-shaped optical fiber as a high sensitive refractive-index sensor to detect changes in the surrounding refractive index was studied. The results for different concentrations of sucrose solution show that a resolution of 1.27 × 103–3.13 × 10−4 RIU is achieved for refractive indices in the range of 1.333 to 1.403, suggesting that the multi-D-shaped fibers are attractive for chemical, biological, and biochemical sensing with aqueous solutions. View Full-Text
Keywords: multi-D-shaped fiber; femtosecond laser; sensor; refractive index multi-D-shaped fiber; femtosecond laser; sensor; refractive index

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This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Chen, C.-H.; Tsao, T.-C.; Tang, J.-L.; Wu, W.-T. A Multi-D-Shaped Optical Fiber for Refractive Index Sensing. Sensors 2010, 10, 4794-4804.

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