Multimode interference devices with single-mode–multimode–multimode fiber structure

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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A Compact Refractometer With High Sensitivity Based on Multimode Fiber Embedded Single Mode-No Core-Single Mode Fiber Structure

Journal of Lightwave Technology ◽

10.1109/jlt.2019.2962196 ◽

2020 ◽

Vol 38 (7) ◽

pp. 1929-1935 ◽

Cited By ~ 2

Author(s):

Shuo Zhang ◽

Sifan Deng ◽

Zemin Wang ◽

Tao Geng ◽

Wenlei Yang ◽

...

Keyword(s):

High Sensitivity ◽

Single Mode ◽

Single Mode Fiber ◽

Fiber Structure ◽

Multimode Fiber

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Temperature Sensing Characteristics Based on Up-Taper and Single Mode–Multimode Fiber Structure

IEEE Photonics Technology Letters ◽

10.1109/lpt.2016.2605675 ◽

2016 ◽

Vol 28 (22) ◽

pp. 2557-2560 ◽

Cited By ~ 10

Author(s):

Yong Zhao ◽

Peng Wang ◽

Riqing Lv ◽

Yang Yang

Keyword(s):

Single Mode ◽

Temperature Sensing ◽

Fiber Structure ◽

Multimode Fiber ◽

Sensing Characteristics

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

Sensors ◽

10.3390/s19071722 ◽

2019 ◽

Vol 19 (7) ◽

pp. 1722 ◽

Cited By ~ 5

Author(s):

Yang ◽

Zhang ◽

Geng ◽

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.

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