Single-Mode to 61 Spots Divider With Multimode Interference in Hexagonal Core Fiber

A grating-less fiber vector bend sensor is demonstrated using a standard single mode fiber spliced to a multimode fiber as a multimode interference device. The ring-shaped light intensity distribution at the end of the multimode fiber is subject to a vector transition in response to the fiber bend. Instead of comprehensive imaging processing for the analysis, the image can be tapped out by a seven-core fiber spliced to the other end of the multimode fiber. The seven-core fiber is further guided to seven single mode fibers via a commercial fan-out device. By comparing the relative light intensities received at the seven outputs, both the bend radius and its direction can be determined. Experiment has shown that a slight bend displacement of 10 µm over a 1.2-cm-long multimode fiber in the X direction (bend angle of 0.382°) causes a distinctive power imbalance of 4.6 dB between two chosen outputs (numbered C4 and C7). For the same displacement in the Y direction, the power ratio between the previous two outputs C4 and C7 remains constant, while the imbalance between another pair (C3 and C4) rises significantly to 7.0 dB.

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Optical Fiber Sensor for Temperature and Strain Measurement Based on Multimode Interference and Square-Core Fiber

Micromachines ◽

10.3390/mi12101239 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1239

Author(s):

Kun Wang ◽

Xingchen Dong ◽

Patrick Kienle ◽

Maximilian Fink ◽

Wolfgang Kurz ◽

...

Keyword(s):

Temperature Sensor ◽

Strain Measurement ◽

Optical Fiber Sensor ◽

High Sensitivity ◽

Single Mode ◽

Fiber Sensor ◽

Multimode Interference ◽

Strain Sensing ◽

Maximal Power ◽

Core Fiber

A variety of specialty fibers such as no-core fiber (NCF) have already been studied to reveal their sensing abilities. In this work, we investigate a specialty fiber, square-core fiber, for temperature and strain sensing. A simple single-mode–multimode–single-mode (SMS) fiber sensor was fabricated, consisting of a 30-cm-long square-core fiber. The experimental results indicate that the maximal wavelength-temperature and wavelength-strain sensitivities are −15.3 pm/∘C and −1.5 pm/με, respectively, while the maximal power-temperature and power-strain sensitivities are 0.0896 dBm/∘C and 0.0756 dBm/με. Analysis of the results suggests that the fiber sensor has the potential to be used as a high-sensitivity temperature sensor with a low strain sensitivity.

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Exposed-core fiber multimode interference sensor

Results in Optics ◽

10.1016/j.rio.2021.100125 ◽

2021 ◽

pp. 100125

Author(s):

Jonas H. Osório ◽

William M. Guimarães ◽

Lu Peng ◽

Marcos A.R. Franco ◽

Stephen C. Warren-Smith ◽

...

Keyword(s):

Multimode Interference ◽

Core Fiber

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Fiber-optic Michelson interferometer based on α-Fe2O3/ZrO2 sensing membrane and its application in trace fluoride-ion detection

Zeitschrift für Naturforschung A ◽

10.1515/zna-2021-0278 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Zizheng Yue ◽

Wenlin Feng

Keyword(s):

Silver Film ◽

Fiber Optic ◽

Michelson Interferometer ◽

Single Mode ◽

Single Mode Fiber ◽

Ion Concentration ◽

Fluoride Ion ◽

Ion Detection ◽

Core Fiber ◽

Sensing Membrane

Abstract In this work, a fiber-optic fluoride-ion-detection Michelson interferometer based on the thin-core fiber (TCF) and no-core fiber (NCF) coated with α-Fe2O3/ZrO2 sensing film is proposed and presented. The single-mode fiber (SMF) is spliced with the TCF and NCF in turn, and a waist-enlarged taper is spliced between them. Then, a silver film is plated on the end face of NCF to enhance the reflection. After the absorption of fluoride ion by the sensing film, the effective refractive index (RI) of the coated cladding will change, which leads to the regular red shift of the interference dip with the increasing fluoride-ion concentration. Thus, the fluoride-ion concentrations can be determined according to the corresponding dip wavelength shifts. The results show that the sensor has an excellent linear response (R 2 = 0.995) with good sensitivity (8.970 nm/ppm) when the fluoride-ion concentration is in the range of 0–1.5 ppm. The response time is about 15 s. The sensor has the advantage of good selectivity, good temperature and pH stabilities, and can be applied to detect fluoride ion effectively.

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An intensity modulated fiber-optic carbon monoxide sensor based on Ag/Co-MOF in-situ coated thin-core fiber

Zeitschrift für Naturforschung A ◽

10.1515/zna-2021-0168 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Lian Wang ◽

Juncheng Zhou ◽

Yuhao Chen ◽

Liu Xiao ◽

Guojia Huang ◽

...

Keyword(s):

Electron Microscopy ◽

Carbon Monoxide ◽

Photoelectron Spectroscopy ◽

Fiber Optic ◽

Temperature Stability ◽

Single Mode ◽

X Ray ◽

Intensity Modulated ◽

Core Fiber

Abstract An intensity modulated fiber-optic carbon monoxide (CO) sensor by integrating in-situ solvothermal-growth Ag/Co-MOF sensing film is fabricated and evaluated. The Michelson interference sensing structure is composed of single-mode fiber (SMF), enlarged taper, thin-core fiber (TCF), and Ag film as the reflector. Ag/Co-MOF was coated on the cladding of the TCF as the sensing material, and the enlarged taper is located between TCF and SMF as the coupler. The structure, morphology, compositions and thermal stability of the Ag/Co-MOF sensing film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), etc. The sensitivity of the sensor is 0.04515 dB/ppm, and the fitting parameter of the CO concentration is 0.99876. In addition, the sensor has the advantages of good selectivity, good signal and temperature stability, and it has potential application in trace CO detection.

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