Article
Engineering, Electrical & Electronic
Enrique Pineiro, Mikel Sagues, Alayn Loayssa
Summary: We present a technique to compensate for the deleterious effects of laser phase noise on long-range distributed acoustic sensors that implement optical pulse compression. The method involves sampling the phase noise of the laser with an auxiliary interferometer and using this information to mitigate its impact on the measured signal. Our method allows OPC-COTDR sensors to demonstrate their full potential for long-range measurements using lasers with less stringent phase noise requirements.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Miguel Soriano-Amat, Hugo F. Martins, Vicente Duran, Luis Costa, Sonia Martin-Lopez, Miguel Gonzalez-Herraez, Maria R. Fernandez-Ruiz
Summary: The phase-sensitive optical time-domain reflectometry (phi OTDR) technique provides spatio-temporal measurements of environmental variables in real time, with a novel approach achieving cm-scale spatial resolutions over 1 km at remarkably low detection bandwidths. This approach utilizes dual-comb spectrometry and random phase-spectral coding to maximize signal-to-noise ratio for sensing schemes.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Engineering, Geological
Chih-Chung Chung, Chih-Ping Lin, Yin Jeh Ngui, Wen-Chin Lin, Chun-Shen Yang
Summary: Time-domain reflectometry (TDR) is a technique that can observe the initiation and evolution of localized shear planes in rock and soil slopes, with suitable temporal and spatial resolutions for landslide monitoring. To better utilize TDR, an improved and standardized technical guide for TDR cable installation and data interpretation is needed. This study developed a large direct shear box to test TDR responses in various cable-grout ground assemblies, in order to model the interaction at the localized shear accurately. The results revealed misconceptions in previous studies and provided new technical recommendations for cable installation and data interpretation, along with a new data reduction method for early detection of localized shear planes.
ENGINEERING GEOLOGY
(2022)
Article
Engineering, Geological
Chih-Chung Chung, Van-Nhiem Tran, Muhammad Azhar
Summary: The suitability of using time-domain reflectometry (TDR) for landslide monitoring and assessment has been validated by field studies, and this study further improves the applicability of TDR through high-gravity centrifuge modeling and modified coaxial cable, successfully detecting small-scale shear displacements and correlating with fault movements.
ENGINEERING GEOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Manuel P. Fernandez, Leonardo Morbidel, Laureano A. Bulus-Rossini, Pablo A. Costanzo-Caso
Summary: The proposed technique for remote monitoring of TDM-PONs utilizes FBG encoders and I-OFDR for high robustness and resolution. Through suitable windowing, a high signal-to-interference ratio can be achieved in highly-dense TDM-PONs.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Huajian Zhong, Cailing Fu, Lijie Wang, Bin Du, Pengfei Li, Yanjie Meng, Lin Chen, Chao Du, Yiping Wang
Summary: This study proposes a high-spatial-resolution optical frequency domain reflectometry method with a single interferometer, using a self-compensation technique to successfully eliminate phase noise and obtain a compensated signal with high signal-to-noise ratio. The high spatial resolution is achieved by analyzing the length of the delay fiber at different measurement distances. This method has great potential in the field of distributed measurement.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Biophysics
Peidong Hua, Zhenyang Ding, Kun Liu, Haohan Guo, Ming Pan, Teng Zhang, Sheng Li, Junfeng Jiang, Tiegen Liu
Summary: A distributed optical fiber biosensor based on tapered fiber and optical frequency domain reflectometry (OFDR) is proposed in this paper. By measuring the shift of the local Rayleigh backscattering spectra (RBS) caused by the refractive index (RI) change of the external medium surrounding the tapered fiber using OFDR, the concentration change of anti-human IgG can be located. This distributed sensor has the potential to achieve micron-level localization of biochemical substances such as cancer cells.
BIOSENSORS & BIOELECTRONICS
(2023)
Article
Chemistry, Analytical
Inigo Corera, Enrique Pineiro, Javier Navallas, Mikel Sagues, Alayn Loayssa
Summary: We present a new long-range traffic monitoring system using fiber-optic distributed acoustic sensing (DAS) for vehicle detection, tracking, and classification. The system achieves high resolution and long range through an optimized setup incorporating pulse compression. The raw data is processed using a novel transformed domain algorithm based on the Hough Transform, enabling automatic vehicle detection and tracking, as well as the extraction of unique vehicle signatures for machine learning-based classification. Experimental results show excellent performance, with a general classification rate of 97.7% for detecting vehicle passing events and 99.6% and 85.7% for specific car and truck passing events, respectively.
Article
Engineering, Multidisciplinary
Chih-Chung Chung, Wei-Feng Chien, Van-Nhiem Tran, Hong-Ting Tang, Zih-Yi Li, Muhammad Saqlain
Summary: Recognizing land subsidence is vital in complex alluvial-basin aquifers, and this study used TDR technology for automatic and high-accuracy measurements. A physical model was used to examine measurement accuracy and standard deviation in different aquifer scenarios. The study also proposed a novel TDR multi-sections schema to extend the measurement range and reduce signal attenuation.
Article
Environmental Sciences
Chih-Chung Chung, Yen-Kai Wang
Summary: A novel real-time SSC monitoring approach using time domain reflectometry (TDR) was proposed in this study. By improving the method and solving practical problems, the measurement stability and accuracy for long-term monitoring in rivers and reservoirs were enhanced. Experimental results showed that the new method has potential for characterizing suspended sediment load more effectively.
WATER RESOURCES RESEARCH
(2022)
Article
Engineering, Electrical & Electronic
M. P. Lipus, S. Kranz, T. Reinsch, C. Cunow, J. Henninges, M. Reich
Summary: This paper presents a novel distributed shear stress sensor that allows for the derivation of fluid rheological parameters along a fiber-optic cable. Laboratory experiments have demonstrated that the sensor can distinguish differences of 1 mPa s dynamic viscosities in a low range.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Engineering, Environmental
Hongting Wan, Xianhui Li, Yusen Luo, Danting Shi, Tengjing Gong, Alicia Kyoungjin An, Senlin Shao
Summary: This study used the ultrasonic time-domain reflectometry (UTDR) technique to detect pore wetting in membrane distillation (MD) and explained the UTDR waveform using optical coherence tomography (OCT) imaging. The results showed that the UTDR could effectively detect the movement of water-vapor interface and monitor pore wetting.
Article
Engineering, Electrical & Electronic
Tingting Yang, Yanbo Xiao, Zengling Ran, Xiu He, Tianqi Shao, Wenyu Wang, Kai Li, Dong Sun, Xiaojuan Qin, Zhengxi He, Yachao Zhang, Dongsheng Ye
Summary: A design method for a weak fiber Bragg grating (FBG) array is proposed, which increases FBG reflectivity along the fiber with limitations set by the dynamic range of a distributed optical fiber sensing (DOFS) system. This method compensates for fiber loss and performance degradation caused by radiation, reducing dynamic range requirements in nuclear environments. Additionally, a short-distance acoustic detection system based on Phi-OTDR is introduced, showing promise in pipeline leakage detection.
IEEE SENSORS JOURNAL
(2021)
Article
Optics
Louis Alliot de Borggraef, Hugues Guillet de Chatellus
Summary: We have developed a novel architecture that enables distributed acoustic sensing in a commercial single-mode fiber. The system has a sub-cm spatial resolution and an interrogation rate of 20 kHz. The architecture utilizes broadband light waveforms, coherent detection, and all-optical pulse compression to achieve high performance in distributed acoustic sensing applications.
Article
Optics
Xin Lu, Peter James Thomas
Summary: Phase-sensitive optical time-domain reflectometry (fOTDR) is a technology for distributed vibration sensing using phase recovery of backscattered light. This study investigates the phase errors introduced by measurement noise in an fOTDR system based on an imbalanced Mach-Zehnder interferometer (IMZI) and a 3 x 3 coupler. The analysis shows that the phase error is inversely proportional to the power of backscattered light and an analytical expression is derived to estimate it. The error using the DCM algorithm is slightly smaller than that using I/Q demodulation, but increases with longer measurement times.
Article
Optics
Yin Xiao, Lina Zhou, Wen Chen
Summary: This paper introduces a correspondence imaging approach for reconstructing high-quality objects through complex scattering media. By deriving a rectified theory and introducing temporal correction, the proposed method eliminates the effect of dynamic scaling factors. Experimental results demonstrate the advantages of the proposed method over conventional methods in complex scattering environments, and it can also be combined with other methods to further enhance the quality of reconstructed objects.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Zengxuan Jiang, Minghao Chao, Qingsong Liu, Bo Cheng, Guofeng Song, Jietao Liu
Summary: In this paper, a multi-focal metalens with high focusing efficiency controlled by circular polarization multiplexing is demonstrated. The metalens can generate four transversely distributed focal points under normal incidence of linearly polarized light, supporting both left-circularly polarized and right-circularly polarized conversion. Furthermore, an oblique incidence metalens is designed to achieve high total focusing efficiency for terahertz waves and provides potential new applications for polarization imaging and detection.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Yiran Wang, Yu Ji, Xuyang Zhou, Xiu Wen, Yutong Li, Zhengjun Liu, Shutian Liu
Summary: This work presents a new reconstruction framework for structured illumination microscopy (SIM), which only requires four raw images and avoids extensive iterative computation. By using checkerboard pattern illumination modulation instead of sinusoidal fringe illumination, the proposed method significantly reduces image acquisition time and achieves higher image reconstruction rate. Additionally, the reconstruction process is non-iterative and not limited by the field of view size.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Qian He, Li Pei, Jianshuai Wang, Jingjing Zheng, Tigang Ning, Jing Li
Summary: This paper proposes a 3D refractive index profile visualization method to demonstrate mode activation and evolution in fiber fusion splicing. The method is validated through experimental results and provides support for various fiber splicing operations and mode coupling modulation.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Qiwei Li, Qiyu Wang, Fang Lu, Yang Cao, Xu Zhao
Summary: LSHIP is a lenslet-array-based snapshot hyperspectral imaging polarimeter that combines spectral polarization modulation with integral field imaging spectrometry. It can simultaneously acquire three-dimensional spatial and spectral data-cubes for linear Stokes parameters in a single snapshot.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Huicong Li, Bing Lv, Meng Tian, Wenzhu Huang, Wentao Zhang
Summary: This study proposes a temperature compensation scheme for unbalanced interferometers using sensing fibers with different temperature coefficients, aiming to resolve the temperature disturbance and achieve high strain resolution. The experimental results confirm the effectiveness of the proposed scheme in high-resolution, long-term, low-frequency, and static strain sensing.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Hongxiang Chang, Rongtao Su, Yuqiu Zhang, Bowang Shu, Jinhu Long, Jinyong Leng, Pu Zhou
Summary: High-speed variable-focus optics provides new opportunities for fiber laser applications in various fields. This paper investigates a non-mechanical axial focus tuning method using coherent beam combining (CBC) technique and proposes a tilt modulation assisted method to extend the tuning range.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Yubo Ni, Shuai Fu, Chaoyang Su, Zhaozong Meng, Nan Gao, Zonghua Zhang
Summary: This paper proposes a surface adaptive fringe pattern generation method to accurately measure specular surfaces, eliminating the out-of-focus effect and improving measurement accuracy and reliability.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Zifan Wang, Tianfeng Zhou, Qian Yu, Zihao Zeng, Xibin Wang, Junjian Hu, Jiyong Zeng
Summary: Fast-axis collimation (FAC) lens arrays are crucial in laser systems, and their precision can be improved through the development of an optical collimation system and the use of thermal compensation to correct for non-uniform thermal expansion.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Jincheng Chen, Qiuyu Fang, Li Huang, Xin Ye, Luhong Jin, Heng Zhang, Yinqian Luo, Min Zhu, Luhao Zhang, Baohua Ji, Xiang Tian, Yingke Xu
Summary: This study developed a novel deep learning accelerated SRRF method that enables super-resolution reconstruction with only 5 low SNR images, and allows real-time visualization of microtubule dynamics and interactions with CCPs.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Pan Liu, Yongqiang Zhao, Ning Li, Kai Feng, Seong G. Kong, Chaolong Tang
Summary: This article presents a technique for inverse design of multilayer deep-etched gratings (MDEG) using a deep neural network with adaptive solution space. The proposed method trains a deep neural network to predict the probability distribution across the discretized space, enabling evaluation of an optimal solution. The results show improved efficiencies using only a reduced dataset and avoiding one-to-many mapping challenges.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Evelina Bibikova, Nazar Al-wassiti, Nataliya Kundikova
Summary: Light beams possess three types of angular momentum, namely spin angular momentum, extrinsic orbital angular momentum, and intrinsic orbital angular momentum. The interaction between these momenta leads to the spin-orbit interaction of light and topological effects. This study predicts a new topological effect resulting from the influence of extrinsic orbital angular momentum on spin angular momentum in converging asymmetrical light beams. It manifests as the transformation of linear polarized light into elliptically polarized light when an asymmetrical beam passes through the left or right half of the focal plane. The measured value of the topological circular amplitude anisotropy R was found to be R = +/- (0.60 +/- 0.08) x 10(-3). This new effect contributes to our understanding of light and has potential applications in developing sensors in optics.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Hamdy H. Wahba
Summary: This study combines multiple-beam Fizeau interference and single-shot digital holographic interferometry to study thick phase objects. By collecting optical phase at different focal planes, the angular spectrum method is used for the first time to retrieve optical phase maps through the focal depth. The proposed method proves to be effective in providing accurate numerical focusing and phase maps reconstruction.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Mohammed A. Isa, Richard Leach, David Branson, Samanta Piano
Summary: Due to the complexity of resolving object form and pose in images, new vision algorithms prioritize identification and perception over accurate coordinate measurement. However, the use of planar targets for coordinate measurement in vision systems has several drawbacks, including calibration difficulties and limited viewing angles. On the other hand, the use of sphere targets is infrequent in vision-based coordinate metrology due to the lack of efficient multi-view vision algorithms for accurate sphere measurements.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Optics
Ildar Rakhmatulin, Donald Risbridger, Richard M. Carter, M. J. Daniel Esser, Mustafa Suphi Erden
Summary: This paper reviews the application of machine learning in laser systems. While machine learning has been widely used in general control automation and adjustment tasks, its application in specific tasks requiring skilled workforces for high-precision equipment assembly and adjustment is still limited. The paper presents promising research directions for using machine learning in mirror positional adjustment, triangulation, and optimal laser parameter selection, based on the recommendations of PRISMA.
OPTICS AND LASERS IN ENGINEERING
(2024)