A new directional bending sensor based on a dual side-hole fiber (DSHF) that can detect both the direction and magnitude of bending in a self-temperature compensated manner is described and experimentally demonstrated. The sensor is based on an in-fiber Mach-Zehnder interferometer (MZI), where a DSHF segment was spliced between two standard single-mode fibers (SMFs) as input and output. The sensor has two orthogonal axes which are formed by both the asymmetry in the side-hole location in DSHF and an offset in the fusion splice between the SMF and DSHF. The visibility in the MZI output intensity and the spectral shifts of MZI fringes show separate responses to the bending curvature and direction, which is a key feature of the directional curvature sensor. An inscribed fiber Bragg grating in the DSHF measure allows the temperature to be measured independently. The sensor can provide salient advantages in its unique capability to precisely quantify the direction and magnitude of bending along with its reproducibility, compactness, and suitability for mass production, which makes it suitable for many practical bending sensing applications.
Bibliographical noteFunding Information:
Manuscript received September 17, 2017; revised November 23, 2017; accepted December 19, 2017. Date of publication December 22, 2017; date of current version January 30, 2018. This work was supported in part by the National Natural Science Foundation of China under Grant 61377096, Grant 61775045, Grant 61605030, and Grant 61422505, in part by the Heilongjiang Young Researcher Support Project under Grant 1253G018, in part by the National Key Scientific Instrument and Equipment Development Project under Grant 2013YQ040815 and Grant 2016YFF 0200704, in part by the Fundamental Research Funds of the Central University, China, and in part by Harbin Engineering University through the 111 Project under Grant B13015. (Corresponding authors: Jianzhong Zhang; Jun Yang.) Y. Tian, Q. Chai, T. Tan, B. Mu, Q. Liu, Y. Liu, J. Ren, J. Zhang, J. Yang, Z. Liu, and L. Yuan are with the Key Laboratory of In-Fiber Integrated Optics of Ministry of Education, Harbin Engineering University, Harbin 150001, China (e-mail: email@example.com; firstname.lastname@example.org).
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering