Influence of temperature on the refractive index sensor based on a core-offset in-line fiber Mach-Zehnder interferometer

A 3-aminopropyl-triethoxysilane (APES) fiber-optic sensor based on a Mach–Zehnder interferometer (MZI) was demonstrated. The MZI was constructed with a core-offset fusion single mode fiber (SMF) structure with a length of 3.0 cm. As APES gradually attaches to the MZI, the external environment of the MZI changes, which in turn causes change in the MZI’s interference. That is the reason why we can obtain the relationships between the APES amount and resonance dip wavelength by measuring the transmission variations of the resonant dip wavelength of the MZI. The optimized amount of 1% APES for 3.0 cm MZI biosensors was 3 mL, whereas the optimized amount of 2% APES was 1.5 mL.

Section: Experimental Methods and Principlementioning

confidence: 99%

Optical Fiber Based Mach-Zehnder Interferometer for APES Detection

Deng

Chen

Huang

et al. 2021

“…So, optical fiber sensors are expected to provide innovative solutions for seawater salinity measurement. Common types of RI fiber sensors include fiber Bragg grating sensors (FBG) [ 7 ], long-period grating sensors (LPG) [ 8 ], surface plasmon resonance sensors (SPR) [ 9 ], cladding mode resonance [ 10 ], and sensors based on the Fabry–Perot (FP) interferometer [ 11 ], Mach-Zehnder interferometer (MZI) [ 12 ], Michelson (ML) interferometer [ 13 ], etc. Typically, all these sensors are based on the resonance-wavelength shift principle [ 14 ], which requires broadband lasers and optical spectrum analyzers [ 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Spatially Modulated Fiber Speckle for High-Sensitivity Refractive Index Sensing

Guo,

Liu,

Zhou

et al. 2023

A fiber speckle sensor (FSS) based on a tapered multimode fiber (TMMF) has been developed to measure liquid analyte refractive index (RI) in this work. By the lateral and axial offset of input light into TMMF, several high-order modes are excited in TMMF, and the speckle pattern is spatially modulated, which affects an asymmetrical speckle pattern with a random intensity distribution at the output of TMMF. When the TMMF is immersed in the liquid analyte with RI variation, it influences the guided modes, as well as the mode interference, in TMMF. A digital image correlations method with zero-mean normalized cross-correlation coefficient is explored to digitize the speckle image differences, analyzing the RI variation. It is found that the lateral- and axial-offsets-induced speckle sensor can enhance the RI sensitivity from 6.41 to 19.52 RIU−1 compared to the one without offset. The developed TMMF speckle sensor shows an RI resolution of 5.84 × 10−5 over a linear response range of 1.3164 to 1.3588 at 1550 nm. The experimental results indicate the FSS provides a simple, efficient, and economic approach to RI sensing, which exhibits an enormous potential in the image-based ocean-sensing application.

“…The silica-based fibers combined with the other materials, including liquids [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], nanoparticles [ 13 , 14 ], and 2D materials (graphene) [ 15 , 16 , 17 , 18 , 19 ], would generate much higher sensitivity to external parameters than that of the intrinsic silica fibers. Various configurations for the FMZIs have been proposed in the literature and have been demonstrated their effectiveness [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Examples include an FMZI with anti-resonance based on an multi-mode fiber (MMF)-HCF-MMF structure for sensing application [ 21 ], tapered fiber-based FMZI for the refractive index (RI) and temperature (T) measurement [ 22 ], core-offset in-line FMZI [ 23 ], an in-line FMZI with thin-core fiber (TCF)-thin fiber-TCF [ 24 ], and SMF-HCF-SMF structures [ 12 , 20 , 28 , <...>…”

Section: Introductionmentioning

confidence: 99%

“…Various configurations for the FMZIs have been proposed in the literature and have been demonstrated their effectiveness [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Examples include an FMZI with anti-resonance based on an multi-mode fiber (MMF)-HCF-MMF structure for sensing application [ 21 ], tapered fiber-based FMZI for the refractive index (RI) and temperature (T) measurement [ 22 ], core-offset in-line FMZI [ 23 ], an in-line FMZI with thin-core fiber (TCF)-thin fiber-TCF [ 24 ], and SMF-HCF-SMF structures [ 12 , 20 , 28 , 29 ]. The structures of the above FMZIs mainly create two arms of the interferometer: The core of the fiber waveguide and the cladding which propagates one or more cladding modes.…”

Section: Introductionmentioning

confidence: 99%

Highly Modulated In-Fiber Mach–Zehnder Interferometer Based on an Ultracompact Leaky-Guided Liquid Core

Lee

Zhuo

Liu

2022

We proposed a novel sensor based on an ultracompact leaky-guided liquid core fiber Mach–Zehnder interferometer (LLCFMZI) for high modulation of an interference spectrum. The sensor structure is based on a micro-sized hollow-core fiber (HCF) splicing a tilt end face single-mode fiber (SMF) to create a miniature oblique gap for the effective access of different liquids. The liquid core with a relatively lower refractive index (RI) than the cladding can achieve a leaky-mode optical waveguide (LMOW) mechanism, and its volume is only approximately 7.85 pL. In addition, the utilized micro-length HCF can reduce the energy loss of core in the LMOW to obtain an acceptable extinction ratio (>30 dB) with high temperature (T) sensitivity in the interference spectra. Experimental results show that the interference spectra can be highly modulated within the wide measurement range of 1250–1650 nm with a steadily linear response for thermal effect. The measured temperature sensitivities (T-sensitivities) of various liquids of DI water, ethanol, and Cargille-liquid (nD = 1.305) are 0.8869, 4.4754, and 4.8229 nm/°C, and the corresponding measured thermal optics coefficient (TOC) are −4.16 × 10−5, −2.11 × 10−4, and −3.6 × 10−4 °C−1, respectively. Measurement results demonstrate that the used liquids with a higher TOC can obtain better T-sensitivity modulation. The highest experimental sensitivity of the liquid-core filled with Cargille-liquid (nD = 1.40) is up to +13.87 nm/°C with a corresponding TOC of −4.07 × 10−4 °C−1. Furthermore, the experimental and theoretical values are in good agreement according to FSR the measuring scheme that investigates the effectiveness of the proposed LLCFMZI.