Cascaded Sagnac loops embedded with two polarization maintaining photonic crystal fibers for highly-sensitive strain measurement

Liu, Qiang, Xing, Liang, Wu, Zhaoxia, Fu, Richard, Li, Shuguang, Xue, Pingsheng, Ng, Wai Pang, Wu, Qiang and Binns, Richard (2021) Cascaded Sagnac loops embedded with two polarization maintaining photonic crystal fibers for highly-sensitive strain measurement. IEEE Transactions on Instrumentation and Measurement, 70. p. 7002309. ISSN 0018-9456

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A strain sensor based on cascaded Sagnac loops with two PMPCFs has been experimentally demonstrated. Air holes distributed on the cross section of PMPCF go through the whole fiber which make the special fiber more sensitive to ambient force compared with conventional optical fiber. The lengths of the two PMPCFs are close, but not the same, to form envelopes on the total output spectrum and then obtain high resolution to the detected parameter by Vernier effect. The influences of the difference in length of the two PMPCFS on spectral envelopes are discussed. As the length of the PMPCF in reference loop increases, free spectrum range of the cascaded Sagnac loops (or envelope period) and magnification decrease. The sensitivities of this strain sensor are calculated by tracking upper- and lower-envelope. Results reveal that its average sensitivity is up to 45.15 pm/με and the corresponding resolution is 0.44 με as strain varies from 0 to 2000 με. Compared with a single Sagnac loop, the sensitivity magnification is about 28.94. The sensing characteristics of a conventional PMF are studied to compare with the PMPCF. Moreover, reversibility has also been proved to possess low error rate. In short, the fiber strain sensor possesses high sensitivity and great reversibility.

Item Type: Article
Additional Information: This work was supported by the National Natural Science Foundation of China (Grant No. 51907017), Key Science and Technology Research Projects of Higher Education Institutions in Hebei Province of China (Grant No. ZD2019304), Fundamental Research Funds for the Central Universities of China (Grant No. N182304011) and China National Fund for Studying Abroad.
Uncontrolled Keywords: strain sensor, cascaded Sagnac loops, photonic crystal fiber, Vernier effect
Subjects: F200 Materials Science
F300 Physics
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: John Coen
Date Deposited: 08 Jan 2021 09:36
Last Modified: 31 Jul 2021 14:51

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