A Demodulation Method of Spatial Domain for Low-Coherence Interferometry With High Accuracy and Adaptability

Wang, Chao; Zhang, Xuezhi; Jiang, Junfeng; Wang, Shuang; Li, Yuanyao

doi:10.1109/jphot.2020.2977839

Cited by 2 publications

(4 citation statements)

References 27 publications

(31 reference statements)

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“…The centroid algorithm, where the position of the center of coherence zone in the fringe pattern was calculated using the following equation [32]:…”

Section: Methodsmentioning

confidence: 99%

Optofluidic Micromachined Platform for Refractive Index Measurement

2022

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We present a combination of micromachined optofluidic platforms equipped with a fiber-optic sensing configuration based on а three-path Mach–Zehnder interferometer (MZI) for simultaneous measurement of the refractive index of liquids and the autocalibration in dynamic regime. The sensing principle is based on the low-coherence interferometry, characterized by a generation of Gaussian enveloped interferograms, for which the position of its maximum depends on the optical path difference (OPD) between the sensing and reference arm of the MZI. When liquid flows through the central microchannel of the optofluidic platform it crosses the light beam between the two optical fibers in the sensing arm causing the OPD change. An algorithm has been applied for the calculation of the refractive index of liquids out of the raw interference signals. We obtained a very good agreement between the experimental results and literature data of refractive indices of subjected fluids. The accuracy of refractive index measurement is approximately 1%, predominantly determined by the accuracy of reading the position of the mechanical scanner. The proposed sensor is attractive for the label-free biological, biochemical, and chemical sensing owing autocalibration and high sensitivity yet consuming a very small sample volume of 1 µL. It is capable to measure the refractive index of various liquids and/or gases simultaneously in the process.

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“…The centroid algorithm, where the position of the center of coherence zone in the fringe pattern was calculated using the following equation [32]:…”

Section: Methodsmentioning

confidence: 99%

Optofluidic Micromachined Platform for Refractive Index Measurement

2022

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“…Through the adjustment of couplers, the initial phase α and β can be regular to 2 3 π and − 2 3 π nearby, afterwards, the value of Δϕ(t) can be obtained by the arcsin operation of Equation (12), and the exact quadrant of Δϕ(t) can be decided by the value of Equation (13). Δϕ(t) reflects the actual vibration signal, with analyzing the Δϕ(t), the actual vibration can be measured.…”

Section: Self-tracking Algorithmmentioning

confidence: 99%

“…9,10 In conventional processed method, due to the relatively robustness of state of sensing path, the direct part of interference light is processed as a time-delayed slow variable, therefore, the DC compensation value is set up unchanged in the following sensing period. [11][12][13][14][15] However, in some situations, when sudden changes are introduced in the sensing path, the direct part of interference light cannot be regarded as a timedelayed slow variable for it will bring a remarkable deviation to the retrieval result.…”

Section: Introductionmentioning

confidence: 99%

“…During the retrieval process, the direct part of interference light, which reflects the static state of the sensing structure, should be compensated in the first place as it is filtered out with asymmetric direct light by the circuit filter 9,10 . In conventional processed method, due to the relatively robustness of state of sensing path, the direct part of interference light is processed as a time‐delayed slow variable, therefore, the DC compensation value is set up unchanged in the following sensing period 11‐15 . However, in some situations, when sudden changes are introduced in the sensing path, the direct part of interference light cannot be regarded as a time‐delayed slow variable for it will bring a remarkable deviation to the retrieval result.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A self‐tracking phase retrieval algorithm used in distributed disturbance sensing

Xiao

2020

Micro & Optical Tech Letters

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The phase-retrieval method with delayed calibration is widely used in fiber-optic sensing structures to extract the distributed vibration messages. Yet, the performance of this method is not satisfactory when sudden changes are introduced in sensing path, for the DC compensation is not a slow variable under this situation. To improve the adjustment of interferometric fiber-optic structure, a self-tracking phase retrieval method is proposed. In the novel algorithm, the static state is tracked by calibrating DC compensation value in each retrieval period. When tested in the real scene with a 20 km-long sensing fiber, the performance of the novel retrieval algorithm has been proved. Experimental results show that, compared with the conventional delayed calibration method, selftracking algorithm brings a better accuracy and uniformity performance in intrusion location test and shows a better adaptability to the environment.

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A Demodulation Method of Spatial Domain for Low-Coherence Interferometry With High Accuracy and Adaptability

Cited by 2 publications

References 27 publications

Optofluidic Micromachined Platform for Refractive Index Measurement

Optofluidic Micromachined Platform for Refractive Index Measurement

A self‐tracking phase retrieval algorithm used in distributed disturbance sensing

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