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Liu J, Ke Y, Yang D, Deng Q, Hei C, Han H, Peng D, Wen F, Feng A, Zhao X. Deep Learning-Based Simultaneous Temperature- and Curvature-Sensitive Scatterplot Recognition. SENSORS (BASEL, SWITZERLAND) 2024; 24:4409. [PMID: 39001188 PMCID: PMC11244590 DOI: 10.3390/s24134409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 06/12/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024]
Abstract
Since light propagation in a multimode fiber (MMF) exhibits visually random and complex scattering patterns due to external interference, this study numerically models temperature and curvature through the finite element method in order to understand the complex interactions between the inputs and outputs of an optical fiber under conditions of temperature and curvature interference. The systematic analysis of the fiber's refractive index and bending loss characteristics determined its critical bending radius to be 15 mm. The temperature speckle atlas is plotted to reflect varying bending radii. An optimal end-to-end residual neural network model capable of automatically extracting highly similar scattering features is proposed and validated for the purpose of identifying temperature and curvature scattering maps of MMFs. The viability of the proposed scheme is tested through numerical simulations and experiments, the results of which demonstrate the effectiveness and robustness of the optimized network model.
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Affiliation(s)
- Jianli Liu
- School of Mechanical Engineering, Yangtze University, Jingzhou 434023, China; (J.L.); (X.Z.)
| | - Yuxin Ke
- School of Electronic Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China; (Y.K.); (C.H.); (A.F.)
| | - Dong Yang
- School of Petroleum Engineering, Yangtze University, Wuhan 430100, China;
| | - Qiao Deng
- School of Petroleum Engineering, Yangtze University, Wuhan 430100, China;
| | - Chuang Hei
- School of Electronic Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China; (Y.K.); (C.H.); (A.F.)
| | - Hu Han
- School of Petroleum Engineering, Yangtze University, Wuhan 430100, China;
| | - Daicheng Peng
- Key Laboratory of Exploration Technologies for Oil and Gas Resources, Yangtze University, Ministry of Education, Wuhan 430100, China;
| | - Fangqing Wen
- Hubei Key Laboratory of Intelligent Vision Based Monitoring for Hydroelectric Engineering, China Three Gorges University, Yichang 443002, China;
| | - Ankang Feng
- School of Electronic Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China; (Y.K.); (C.H.); (A.F.)
| | - Xueran Zhao
- School of Mechanical Engineering, Yangtze University, Jingzhou 434023, China; (J.L.); (X.Z.)
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Zhou W, Zhao M, Srinivasan VJ. Interferometric diffuse optics: recent advances and future outlook. NEUROPHOTONICS 2023; 10:013502. [PMID: 36284601 PMCID: PMC9587754 DOI: 10.1117/1.nph.10.1.013502] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
The field of diffuse optics has provided a rich set of neurophotonic tools to measure the human brain noninvasively. Interferometric detection is a recent, exciting methodological development in this field. The approach is especially promising for the measurement of diffuse fluctuation signals related to blood flow. Benefitting from inexpensive sensor arrays, the interferometric approach has already dramatically improved throughput, enabling the measurement of brain blood flow faster and deeper. The interferometric approach can also achieve time-of-flight resolution, improving the accuracy of acquired signals. We provide a historical perspective and summary of recent work in the nascent area of interferometric diffuse optics. We predict that the convergence of interferometric technology with existing economies of scale will propel many advances in the years to come.
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Affiliation(s)
- Wenjun Zhou
- China Jiliang University, College of Optical and Electronic Technology, Hangzhou, China
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Mingjun Zhao
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- New York University Langone Health, Department of Radiology, New York, New York, United States
| | - Vivek J. Srinivasan
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- New York University Langone Health, Department of Radiology, New York, New York, United States
- New York University Langone Health, Department of Ophthalmology, New York, New York, United States
- New York University Langone Health, Tech4Health Institute, New York, New York, United States
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Arístizabal VH, Vélez FJ, Rueda E, Gómez ND, Gómez JA. Numerical modeling of fiber specklegram sensors by using finite element method (FEM). OPTICS EXPRESS 2016; 24:27225-27238. [PMID: 27906296 DOI: 10.1364/oe.24.027225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Although experimental advances in the implementation and characterization of fiber speckle sensor have been reported, a suitable model to interpret the speckle-pattern variation under perturbation is desirable but very challenging to be developed due to the various factors influencing the speckle pattern. In this work, a new methodology based on the finite element method (FEM) for modeling and optimizing fiber specklegram sensors (FSSs) is proposed. The numerical method allows computational visualization and quantification, in near field, of changes of a step multi-mode fiber (SMMF) specklegram, due to the application of a uniformly distributed force line (UDFL). In turn, the local modifications of the fiber speckle produce changes in the optical power captured by a step single-mode fiber (SSMF) located just at the output end of the SMMF, causing a filtering effect that explains the operation of the FSSs. For each external force, the stress distribution and the propagations modes supported by the SMMF are calculated numerically by means of FEM. Then, those modes are vectorially superposed to reconstruct each perturbed fiber specklegram. Finally, the performance of the sensing mechanism is evaluated for different radius of the filtering SSMF and force-gauges, what evidences design criteria for these kinds of measuring systems. Results are in agreement with those theoretical and experimental ones previously reported.
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Farahi S, Ziegler D, Papadopoulos IN, Psaltis D, Moser C. Dynamic bending compensation while focusing through a multimode fiber. OPTICS EXPRESS 2013; 21:22504-14. [PMID: 24104139 DOI: 10.1364/oe.21.022504] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Multimode fiber endoscopes have recently been shown to provide sub-micrometer resolution, however, imaging through a multimode fiber is highly sensitive to bending. Here we describe the implementation of a coherent beacon source placed at the distal tip of the multimode fiber, which can be used to compensate for the effects of bending. In the first part of this paper, we show that a diffraction limited focused spot can be generated at the distal tip of the multimode fiber using the beacon. In the second part, we demonstrate focusing even when the fiber is bent by dynamically compensating for it. The speckle pattern at the proximal fiber end, generated by the beacon source placed at its distal end, is highly dependent on the fiber conformation. We experimentally show that by intensity correlation, it is possible to identify the fiber conformation and maintain a focus spot while the fiber is bent over a certain range. Once the fiber configuration is determined, previously calibrated phase patterns could be stored for each fiber conformation and used to scan the distal spot and perform imaging.
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Yuan Y, Wu G, Li X, Fan Y, Wu X. Effects of twisting and bending on LP21 mode propagation in optical fiber. OPTICS LETTERS 2011; 36:4248-4250. [PMID: 22048380 DOI: 10.1364/ol.36.004248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Twisting and bending characteristics of low-multimode LP21 mode propagation in optical fibers is presented for the first time. Theoretical fiber mode modeling, combining geometrical rotation with opto-elastic effects, demonstrates that the propagation of the LP21 mode is bending-effect-immune. Experimental testing verifies that the LP21 mode specklegram rotates 0.9112 of the fiber twist angle in a fused silica fiber, independent of any fiber bending. This characteristic allows for the LP21 mode to be highly applicable in fiber specklegram sensors.
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Affiliation(s)
- Yufeng Yuan
- Department of Optical Engineering, Zhejiang University, Hangzhou, 310027, China.
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Li J, Cai H, Geng J, Qu R, Fang Z. Specklegram in a multiple-mode fiber and its dependence on longitudinal modes of the laser source. APPLIED OPTICS 2007; 46:3572-8. [PMID: 17514317 DOI: 10.1364/ao.46.003572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A specklegram in a multimode fiber (MMF) has successfully been used as a sensor for detecting external disturbance. Our experiments showed that the sensitivity in the sensor with a multiple longitudinal-mode laser as its source was much higher than that with a single longitudinal-mode laser. In addition, the near-field pattern observations indicated that the coupling between different transverse modes in the MMF is quite weak. Based on the experimental results, a theoretical model for the speckle formation is proposed, taking a bend-caused phase factor into consideration. It is shown in the theoretical analysis that the interferences between different longitudinal modes make a larger contribution to the specklegram signals.
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Affiliation(s)
- Jun Li
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China.
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Malki A, Gafsi R, Michel L, Labarrνre M, Lecoy P. Impact and vibration detection in composite materials by using intermodal interference in multimode optical fibers. APPLIED OPTICS 1996; 35:5198-5201. [PMID: 21102957 DOI: 10.1364/ao.35.005198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An optical fiber sensor based on the intermodal interference principle is integrated in a composite material to detect impacts and vibrations. Six fibers are integrated at the top of a carbon/epoxy composite panel so as to form a grid into the structure. Spectral and temporal responses to impacts and acoustic vibrations of the sensor are compared with a piezoelectric accelerometer. The tests proved the facility of integration and the high sensitivity of the device. The location of impacts is performed with this arrangement by measuring the arrival times of the front waves to the fibers.
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