Multiple parameter vector bending and high-temperature sensors based on asymmetric multimode fiber Bragg gratings inscribed by an infrared femtosecond laser

Department of Electrical Engineering, The Pennsylvania State University, University Park, 16802, USA.
Optics Letters (Impact Factor: 3.29). 07/2006; 31(12):1794-6. DOI: 10.1364/OL.31.001794
Source: PubMed


We present a multiple parameter integrated fiber sensor that can detect vector bending and ambient temperature simultaneously with a single asymmetric multimode fiber Bragg grating. Multimode Bragg gratings were fabricated in an all-silica core fiber by an infrared femtosecond laser, which showed multiple transmission dips in the transmission spectrum. Bending and ambient temperature fluctuations affect the shapes of multiple transmission dips in different ways. In bending, different dips have different sensitivities. On the other hand, temperature fluctuations tended to influence the dips uniformly across different dips. By analyzing the changing spectrum of dips, one can distinguish the changes induced by bending or temperature fluctuations. Furthermore, the high thermal stability of Bragg gratings inscribed by an infrared femtosecond laser can make this double parameter fiber sensor work in very harsh, high-temperature environments.

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    • "The temperature, and strain responses of FBG-in-SMS are easily separated and measured. Comparing with multi-mode FBG reported previously [27] [28] [29] [30], the FBGin-SMS combines the SMS spectral characteristics and the grating spectra, making it stable and readily controlled. It also provides a method to tune and optimize the SMS transmission spectrum for sensing when writing a FBG in the SMS structure by tuning the interference through tuning the refractive index. "
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    ABSTRACT: We propose a compact multi-parameter fibre sensing module based on a fibre Bragg grating (FBG) in single─multi─single mode fibre structure (FBG-in-SMS). We experimentally demonstrated that the FBG-in-SMS can measure temperature and strain simultaneously. In addition, we found that the process of writing FBG in SMS could be an effective technique for tuning and optimizing SMS spectrum for sensing.
    Measurement Science and Technology 04/2014; 25(5). DOI:10.1088/0957-0233/25/5/055205 · 1.43 Impact Factor
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    • "Here, we used this fiber for FBGs fabricating. Refractive index gratings are being widely used in temperature sensors [6] [7]. So, it is possible to measure temperature gradients inside the gyroscope fiber loop using FBGs array written in this fiber type. "
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    ABSTRACT: The article presents the results of writings of type I and type II fiber Bragg gratings in birefringent optical fibers with an elliptical stress cladding by a single 20 ns pulse of KrF excimer laser (248 nm). Experimental results on visualization and thermal annealing of these gratings are presented.
    V International Research and Practice Conference, Munich, Germany; 10/2013
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    ABSTRACT: We present a fibre optic sensing system for simultaneous strain and temperature measurement based on a narrow band variable optical reflector. The variable optical reflector comprises a single mode fibre Bragg grating and a fibre mode converter. A 2 µm m−1 strain resolution is achievable over a range of 2000 µm m−1 with a temperature accuracy of 0.3 °C. A strain sensor with a range of 12 000 µm m−1 is also demonstrated. The sensing system shows high strain and temperature sensitivities with very good stability.
    Measurement Science and Technology 05/2007; 18(7):1867. DOI:10.1088/0957-0233/18/7/011 · 1.43 Impact Factor
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