Refractive index and strain sensor based on twin-core fiber with a novel T-shaped taper

Abstract A compact in-fiber Mach–Zehnder interferometer (MZI) based on twin-core fiber (TCF) with a novel T-shaped taper is proposed and demonstrated. The taper was firstly fabricated by a short section of TCF, and then spliced with a section of cleaved single mode fiber (SMF). When the light transmit into the TCF, multiple modes will be excited and will propagate within the TCF. In experiment, the proposed device had a maximum interferometric extinction ratio about 17 dB. And the refractive index (RI), strain, and temperature response properties of the sensor have been investigated, which show a relatively high RI, strain sensitivity and low temperature cross sensitivity. Hence, the sensor can be a suitable candidate in the biochemical and physical sensing applications. And due to its easy and controllable fabrication, the novel drawing technology can be applied to more multicore optical fibers.

[1]  Jing Zhao,et al.  Asymmetrical in-fiber Mach-Zehnder interferometer for curvature measurement. , 2015, Optics express.

[2]  Li Pei,et al.  Fiber-Optic Laser Sensor Based on All-Fiber Multipath Mach–Zehnder Interferometer , 2016, IEEE Photonics Technology Letters.

[3]  Tao Wei,et al.  Fiber Inline Core–Cladding-Mode Mach–Zehnder Interferometer Fabricated by Two-Point CO$_{2}$ Laser Irradiations , 2009, IEEE Photonics Technology Letters.

[4]  Alan D. Kersey,et al.  Analysis of the response of long period fiber gratings to external index of refraction , 1998 .

[5]  I. Bennion,et al.  Sampled fiber Bragg grating for simultaneous refractive-index and temperature measurement. , 2001, Optics letters.

[6]  Sailing He,et al.  Optical Refractive-Index Sensor Based on Dual Fiber-Bragg Gratings Interposed With a Multimode-Fiber Taper , 2007, IEEE Photonics Technology Letters.

[7]  Hong-Bo Sun,et al.  Compact Mach–Zehnder Interferometer Based on Tapered Hollow Optical Fiber , 2015, IEEE Photonics Technology Letters.

[8]  Qiang Wu,et al.  High sensitivity refractive index sensor based on a tapered small core single-mode fiber structure. , 2015, Optics letters.

[9]  A. Zhang,et al.  Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor , 2005, IEEE Photonics Technology Letters.

[10]  Qiang Wu,et al.  High-sensitivity, evanescent field refractometric sensor based on a tapered, multimode fiber interference. , 2011, Optics letters.

[11]  Jianquan Yao,et al.  Low-temperature cross-talk magnetic-field sensor based on tapered all-solid waveguide-array fiber and magnetic fluids. , 2015, Optics letters.

[12]  Xueguang Qiao,et al.  Ultrahigh-Temperature Chirped Fiber Bragg Grating Through Thermal Activation , 2015, IEEE Photonics Technology Letters.

[13]  Matthew D. Rogge,et al.  Shape sensing using multi-core fiber optic cable and parametric curve solutions. , 2012, Optics express.

[14]  Jing Li,et al.  Refractive index sensor based on tapered multicore fiber , 2017 .

[15]  SMF Taper Evanescent Field-Based RI Sensor Combined With Fiber Loop Ring Down Technology , 2015, IEEE Photonics Technology Letters.

[16]  Tao Zhu,et al.  Refractive index sensing based on Mach-Zehnder interferometer formed by three cascaded single-mode fiber tapers. , 2011, Applied optics.