Abstract

A femtosecond (fs) laser fabricated refractive index (RI) modulated multimode fiber (MMF) for high sensitivity vector bending measurement is presented. A fs laser-induced local positive RI modulation in the MMF core results in a non-circular symmetric RI distribution of the MMF. Such a RI-modulated MMF used in single-mode-multimode-single-mode (SMS) fiber structure exhibits a bending-dependent spectral shift response. Due to the large core size of the MMF, the RI modulated area can be relatively far away from the fiber core axis, which in turn results in a greater effective RI change during bending. Experimental results show that the highest bending sensitivity of −45.8 nm/m⁻¹ is achieved at 0° orientation with the resonant wavelength of 1554.4 nm. In addition to its high sensitivity and simple structure, this vector bending sensor exhibits ultra-low temperature crosstalk in bending measurements, as low as 0.0002 m⁻¹/°C, which makes it an excellent candidate for accurate vector bending monitoring applications.

Femtosecond-induced spiral micro-structured SMS fiber structure for refractive index measurement

F. Liu, H. F. Lin, Y. Liu, A. Zhou, and Y. T. Dai
Opt. Express 26(13) 17388-17396 (2018)

High-sensitivity vector bend sensor based on a fiber directional coupler inscribed by a femtosecond laser

Ke Tian, Mingyuan Zhang, Chuanzhen Zhao, Huibin Li, Shilong Li, Yuxuan Jiang, Elfed Lewis, Gerald Farrell, and Pengfei Wang
Opt. Lett. 48(6) 1498-1501 (2023)

Highly sensitive vector bending sensor based on an embedded multimode D-shaped LPFG

Xiren Jin, Zihang Xiang, Chupeng Lu, Shuo Zhang, Zeju Rui, Yang Yi, Xian Xu, Jiabin Wang, Cuiting Sun, Tao Geng, Chunying Guan, Xinghua Yang, Weimin Sun, and Libo Yuan
Opt. Express 29(15) 22813-22822 (2021)

Low-temperature crosstalk and surrounding refractive index insensitive vector bending sensor based on hole-assistant dual-core fiber

Jing Yang, Chunying Guan, Jiaming Zhang, Mingjie Wang, Min Yang, Zheng Zhu, Pengfei Wang, Jun Yang, and Libo Yuan
Appl. Opt. 58(24) 6597-6603 (2019)

All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating

Shuo Zhang, Tao Geng, Huiwen Niu, Xiang Li, Yunxiang Yan, Cuiting Sun, Sifan Deng, Zemin Wang, Shengjia Wang, Wenlei Yang, Weimin Sun, and Libo Yuan
Opt. Lett. 45(15) 4172-4175 (2020)