scholarly journals A Refractive Index Sensitive Liquid Level Monitoring Sensor Based on Multimode Interference

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 89
Author(s):  
Fan Zhang ◽  
Shuguang Li ◽  
Xin Yan ◽  
Xuenan Zhang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Silica Glass ◽  
Pure Water ◽  
Beam Propagation Method ◽  
High Sensitivity ◽  
Single Mode ◽  
Liquid Level ◽  
Multimode Interference ◽  
Glycerin Solution ◽  
Level Monitoring

According to the beam propagation method, a fiber refractive index-sensitive multimode interference (MMI) structure fabricated by splicing a self-made silica glass rod between two single mode fibers (SMF–NCF (no core fiber)–SMF structure) is proposed for liquid level monitoring. Theoretical and experimental investigation was carried out meticulously using a 4.5 cm and a 9.5 cm long silica glass rod. It is proved that the simple and economical sensor with the shorter length has high sensitivity, satisfactory repeatability, and favorable stability. The sensitivity climbs with the increase in refractive index of the measured liquid, which is 204 pm/mm for pure water, 265.8 pm/mm for 10% glycerin solution, and 352.5 pm/mm for 25% glycerin solution. The proposed sensor can be standardized in certain application circumstances to achieve accurate liquid level monitoring.

scholarly journals High Sensitivity Refractometer Based on a Tapered-Single Mode-No Core-Single Mode Fiber Structure

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1722 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Geng ◽  
Li ◽  
Li ◽  
...  
Keyword(s):  
Refractive Index ◽  
Contrast Ratio ◽  
High Sensitivity ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Experimental Investigations ◽  
Multimode Interference ◽  
Fiber Structure ◽  
Index Unit ◽  
Good Agreement

We have proposed a novel tapered-single mode-no core-single mode (TSNS) fiber refractometer based on multimode interference. The TSNS structure exhibits a high contrast ratio (＞15 dB) and a uniform interference fringe. The influence of different lengths and diameters of the TSNS on the refractive index unit (RIU) sensitivity was investigated. The experimental investigations indicated a maximum sensitivity of 1517.28 nm/RIU for a refractive index of 1.417 and low-temperature sensitivity (＜10 pm/ºC). The experimental and simulation results are also in good agreement.

Strain, torsion and refractive index sensors based on helical long period fibre grating inscribed in small-core fibre for structural condition monitoring

2021 ◽  
Vol 24 (6) ◽  
pp. 1248-1255
Author(s):  
Cailing Fu ◽  
Yi-Qing Ni ◽  
Tong Sun ◽  
Yiping Wang ◽  
Siqi Ding ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Single Mode ◽  
Structural Condition ◽  
Core Diameter ◽  
Small Core ◽  
Long Period ◽  
Sensing Applications ◽  
Core Fibre ◽  
Refractive Index Sensors

This study is intended to develop long period fibre grating sensors for potential applications in environmental and durability monitoring of coastal structures. High-quality helical long period fibre gratings (HLPFGs) are inscribed in different types of small-core single mode fibre (SMF) by use of hydrogen-oxygen flame heating technique. A detailed investigation of the effect of core diameter on their transmission spectrum and optimum length of the HLPFG has been pursued. A longer length is required to achieve the same coupling attenuation in a smaller-core SMF than that of a larger-core fibre. The strain, torsion and refractive index (RI) properties of the HLPFG is investigated experimentally to develop a high-sensitivity sensor. The experimental results show that the strain sensitivity could be enhanced by means of employing a larger-core diameter SMF. Moreover, the HLFPGs are also sensitive to the torsion and external RI. Hence, such HLFPGs have great potential for sensing applications.

Spatial-frequency multiplexing of high-sensitivity liquid level sensors based on multimode interference micro-fibers

2020 ◽  
Vol 307 ◽  
pp. 111985
Author(s):  
Marko Galarza ◽  
Rosa Ana Perez-Herrera ◽  
Daniel Leandro ◽  
Aitor Judez ◽  
Manuel López-Amo
Keyword(s):  
Spatial Frequency ◽  
High Sensitivity ◽  
Liquid Level ◽  
Multimode Interference ◽  
Frequency Multiplexing ◽  
Level Sensors

Temperature-insensitive intensity-modulation liquid refractive index sensor based on fiber-optic Michelson probe structure

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chen Zheng ◽  
Wenlin Feng ◽  
Xiaozhan Yang ◽  
Guojia Huang ◽  
Lian Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Beam Propagation Method ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Intensity Change ◽  
Refractive Index Sensor ◽  
Silver Mirror ◽  
Core Fiber ◽  
Core Modes ◽  
Theoretical Results

Abstract A novel liquid refractive index sensor based on the connected single-mode fiber (SMF), no-core fiber (NCF), four-core fiber (FCF), and silver mirror (SM) to form an SMF–NCF–FCF–SM Michelson probe structure is proposed and fabricated. The change of light field in the probe structure has been simulated by the light-beam propagation method. The theoretical results show that light is excited in the NCF and couples into the cores and cladding of FCF at the junction of NCF and FCF. The interference fringes are generated between the cladding modes and core modes of FCF. The sensitivities of the probe in NaCl, sucrose, and glycerol are 171.75 dB/RIU, 121.41 dB/RIU, and 207.50 dB/RIU, respectively. The temperature sensitivity is 0.05 nm/°C, and the intensity change of temperature (≤0.046 dB/°C) is very small and has little effect on the liquid refractive index. Thus, the cross-sensitivity of temperature for the liquid refractive index can be removed. The proposed probe structure has the advantages of easy fabrication, good stability, and linear response, having potential application in the liquid refractive index monitoring environments.

Graphene oxide-polymethylmethacrylate polymer waveguide device based on near infrared fingerprint spectrum for refractive index sensing

2017 ◽  
Vol 40 (8) ◽  
pp. 2607-2610
Author(s):  
Botao Wang ◽  
Qi Wang ◽  
Lingxin Kong ◽  
Riqing Lv
Keyword(s):  
Refractive Index ◽  
Graphene Oxide ◽  
Near Infrared ◽  
High Sensitivity ◽  
Single Mode ◽  
Glycerol Solution ◽  
Refractive Index Measurement ◽  
Polymer Waveguide ◽  
Refractive Index Sensing ◽  
High Measurement

A graphene oxide-polymethylmethacrylate (GO-PMMA) microfiber sensor is proposed and experimentally demonstrated in this paper, which is based on the absorption principle of near infrared spectra for external refractive index sensing. The sensor was fabricated by splicing a section of 1 mm GO-PMMA between two tapered single mode fibers. The hydrophilic groups of graphene oxide can be used to measure the proportion of water in glycerol solution, and achieve the goal of refractive index measurement indirectly. Experiments were conducted for moisture content of 4.3%~45% (refractive index range from 1.3400 to 1.4054) in glycerin solution. Different concentrations of glycerol solution have different intensities of absorption peaks near 1530 nm wavelength. The absorption peak power near 1530 nm wavelength responses to the external refractive index was experimentally studied. The results show that the sensor possesses a high sensitivity of 167.39 dB/RIU in the refractive index range of 1.34~1.41 and has a good linearity response to external refractive index. The proposed sensor is attractive owing to its high measurement speed, accurate, no pollution and lower cost, and is suited for long-term online real-time measurement.

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