1. Demodulation method for tilted fiber Bragg grating refractometer with high sensitivity.
- Author
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Pham, Xuantung, Si, Jinhai, Chen, Tao, Wang, Ruize, Yan, Lihe, Cao, Houjun, and Hou, Xun
- Subjects
DEMODULATION ,FIBER Bragg gratings ,REFRACTOMETERS ,REFRACTIVE index measurement ,FEMTOSECOND lasers - Abstract
In this paper, we propose a demodulation method for refractive index (RI) sensing with tilted fiber Bragg gratings (TFBGs). It operates by monitoring the TFBG cladding mode resonance “cut-off wavelengths.” The idea of a “cut-off wavelength” and its determination method are introduced. The RI sensitivities of TFBGs are significantly enhanced in certain RI ranges by using our demodulation method. The temperature-induced cross sensitivity is eliminated. We also demonstrate a parallel-double-angle TFBG (PDTFBG), in which two individual TFBGs are inscribed in the fiber core in parallel using a femtosecond laser and a phase mask. The RI sensing range of the PDTFBG is significantly broader than that of a conventional single-angle TFBG. In addition, its RI sensitivity can reach 1023.1 nm/refractive index unit in the 1.4401–1.4570 RI range when our proposed demodulation method is used. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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