All-fiber Mach–Zehnder interferometer with dual-waist PCF structure for highly sensitive refractive index sensing
- 53 Downloads
A simple, highly sensitive, and all-fiber Mach–Zehnder interferometer (MZI) refractive index (RI) sensor was proposed and experimentally demonstrated, which was fabricated by welding a dual-waist photonic crystal fiber (DWPCF) with two single-mode fibers. The two waists in the PCF, which acted as splitter and combiner of the MZI, could be simply formed by fusion-tapering technique. The high-order cladding modes could be largely excited in the first waist region and propagated along the cladding until the second waist region, where it would be returned into the fiber core and interfered with the core mode. When the RI around the DWPCF changed, an effective RI variation of the cladding modes might generate, which resulted in the shift of interference spectrum. Therefore, the external RI variation could be obtained by monitoring the wavelength position of the interference pattern. Experimental results showed that the interference wavelength shifted with the increase of the external RI, and high measurement sensitivity of 263.5 nm/RIU was achieved with good linearity.
This work was supported in part by the National Natural Science Foundation of China under Grants 61603265, 61703080 and 61273059, the Fundamental Research Funds for the Central Universities under Grant N160408001 and N180404011, the Doctoral Research Project of Shenyang Normal University under Grant BS201702, the Liaoning Province Natural Science Foundation under Grant 20170540314, and the State Key Laboratory of Synthetical Automation for Process Industries under Grant 2013ZCX09. We would acknowledge Bo Han for his help in measuring NaCl solution. Ya-nan Zhang acknowledges the financial support from the China Scholarship Council for his Visiting Scholarship no. 201806085010.
- 9.P.C. Chen, X.W. Shu, H.R. Cao, Novel compact and low-cost ultraweak Fabry–Perot interferometer as a highly sensitive refractive index sensor. IEEE Photon. J. 9(5), 7105810 (2017)Google Scholar
- 17.Y. Zhao, D. Wu, Q. Wang, All-fiber Mach–Zehnder interferometer using a tapered photonic crystal fiber for refractive index measurement. IEEE Sens. 2014, 1080–1083 (2014)Google Scholar