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High sensitivity detection of partial discharge acoustic emission within power transformer by sagnac fiber optic sensor
摘要： Partial discharge acoustic detection is an important monitoring tool for power transformer diagnosis, which was traditionally performed by mounting the piezoelectric transducers on the oil tank surface. The disadvantage of partial discharge acoustic detection is its low sensitivity when partial discharge occurs inside the winding, which greatly compromises the value of partial discharge acoustic detection. Fiber optic sensors that can be deployed within power transformer are expected to be a potential solution. In this research, we used a Sagnac fiber sensor system built in lab to investigate the benefits of using fiber optic sensor for partial discharge acoustic detection. Acoustic pulses were induced in oil outside the winding and in oil duct inside the winding of a single phase 50 kV transformer. Although both fiber optic sensor and piezoelectric sensor can effectively detect the acoustic pulses outside the winding, fiber optic sensor gained a much better sensitivity over piezoelectric transducer to detect the acoustic pulses originated inside the winding. We envisage that the proposed fiber sensor can be deployed in power transformers to significantly enhance the detection performance of acoustic emission induced by partial discharge.
关键词： acoustic transducers,power transformers,partial discharges,optical fiber transducers
更新于2025-09-09 09:28:46
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Noninvasive Measurement of Heart Rate and Respiratory Rate for Perioperative Infants
摘要： A novel fiber optic sensor is designed with mesh microbenders for simultaneous perioperative measurement of heart rate (HR) and respiratory rate (RR) for infants. The feasibility of the mesh microbend fiber sensor was evaluated in 10 infants, ranging from 1 to 12 months in a prospective cross-sectional observational study with the sensor placed under the subjects in the perioperative period. All study subjects received standard intraoperative physiological monitoring of their vital signs. The high order harmonic sensing signals associated with other filtering methods are used for the removal of motion noise. The study results showed good agreement in the measurement of HR and RR between the proposed microbend fiber sensor and the current standard physiological monitoring used in medical settings.
关键词： heart rate (HR),perioperative infant monitoring,respiratory rate (RR),Microbend optical fiber
更新于2025-09-09 09:28:46
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Analytical Analysis and Experimental Validation of a Multi-parameter Mach-Zehnder Fiber Optic Interferometric Sensor
摘要： Here we report a simple analytical technique to model a Mach–Zehnder fiber optic interferometric sensors that allow us to predict and calculate via computer simulations parameters that are not easily obtained experimentally. This model was calibrated and compared with experimental data using a 120 mm sensor for measurements of temperature, refractive index and water level. For instance, we were able to calculate the effects on the cladding index caused by the variation of those physical effective parameters. Moreover, this analysis could further our understanding of such sensors and allow us to make predictions about their use in different applications and even their behavior with different sensing lengths.
关键词： optical fiber devices,analytical model,Optical fiber interference,optical fiber applications,optical interferometry
更新于2025-09-04 15:30:14
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Distributed Fiber Optical Technology for Damage Identification of Engineering Structure
摘要： To conduct optical fiber monitoring rock slide model test and optical fiber monitoring of steel concrete interface slip model test, the large tri-axial shear test of geotechnical engineering was used. First, the data of sliding distance and optical loss and their dynamic range were obtained. Second, the slide distance and fiber loss relation curve and the fitting equation were worked out. Finally, the typical applications of optical fiber sensing technology in Rock Engineering (high slope engineering, rock foundation of Dam Engineering) slope stability and geological disaster monitoring were put forward. The results showed that optical fiber sensing was very sensitive, and the loss value was 30 to 50dB. The dynamic range of rock slide monitoring fiber was 3 to 3.5mm, and the dynamic range of the interface slip monitoring fiber was 1.6mm. Thus, the sensing system can detect the sliding process of the interface between the concrete and the steel plate. It provides some reference for the sliding monitoring of the composite materials.
关键词： Optical fiber sensing technology,engineering structure damage,sliding distance-fiber loss
更新于2025-09-04 15:30:14
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Effective method for determining chromatic dispersion from a spectral interferogram
摘要： We present a novel method for determining chromatic dispersion profile from a broadband spectral interferogram obtained by using a white-light interferometry technique. The proposed method is based on direct calculations of a second derivative of the registered spectral intensity at extremal points which in result gives a spectral phase difference derivative further used for dispersion determining. Although the method is best suited for processing interferograms with modulation around a zero level (zero-mean value interferograms) and slowly changing envelope, the conducted numerical tests show that it is highly tolerable to different types of perturbations of the input interference signal. The proposed method can be applied both to spectral interferograms with monotonically changing phase difference as well as containing stationary phase difference points. We demonstrate the effectiveness and accuracy of the proposed method in measurements of chromatic dispersion of commercially available samples like the BK7 glass plate and the Corning SMF-28 optical fiber.
关键词： chromatic dispersion,optical interferometry,Optical fiber dispersion
更新于2025-09-04 15:30:14
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Advanced Modulation Techniques for Flexible Optical Transceivers: the Rate/Reach Trade-off
摘要： This tutorial paper reviews advanced modulation techniques that have been proposed in the literature for the implementation of flexible (or reconfigurable) transceivers, which are fundamental building blocks of next-generation software-defined optical networks. Using a common reference multi-span propagation system scenario, the performance of transceivers employing standard quadrature-amplitude modulation with variable-rate forward error correction, probabilistic constellation shaping and time-domain hybrid formats is assessed, highlighting the achievable flexibility in terms of continuous trade-off between transmission rate and distance. The combination of these techniques with sub-carrier multiplexing, which enables an increase of the fiber nonlinearity tolerance thanks to the optimization of the symbol rate per sub-carrier, is also discussed.
关键词： coherent detection,Optical fiber communication,hybrid QAM,flexible optical transceivers,modulation formats,subcarrier multiplexing,probabilistic shaping
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Photonics Conference (IPC) - Reston, VA, USA (2018.9.30-2018.10.4)] 2018 IEEE Photonics Conference (IPC) - 10-Gb/s Transmission Over 10-m SI-POF with M-PAM and Multilayer Perceptron Equalizer
摘要： We demonstrate the gigabit-per-second transmission over a step-index plastic optical fiber (SI-POF) of 10-m length with a pulse-amplitude modulation (PAM). A multilayer perceptron-based equalizer is used to mitigate an intersymbol interference and non-linearity in the system. Using this equalizer with 32-PAM, a data rate of 10 Gb/s is achieved over the 10-m SI-POF at a bit error rate of 10?2, which is below the 20% forward error correction limit.
关键词： multilayer perceptron (MLP),Polymer optical fiber (POF),pulse amplitude modulation (PAM),decision feedback equalizer,non-linearity
更新于2025-09-04 15:30:14
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SPR based fiber optic sensor using IMO thin film: towards wide wavelength tunability from visible to NIR
摘要： Due to existence of free electrons, conducting metal oxides (CMOs) such as indium molybdenum oxide, can support surface plasmon resonance (SPR) at the interface of CMO and the dielectric. This research provides first theoretically implementation of Indium molybdenum oxide (IMO) as plasmonic layer in SPR fiber optic sensor. We demonstrate how changing the oxygen contents during IMO layer deposition could tune the operational wavelength of sensing probe in a wide range from visible to NIR which has a great significance in many biological and chemical environmental applications. Moreover, sensitivity and figure of merit of the proposed sensor have been calculated and compared for IMO thin films prepared at different oxygen contents.
关键词： Surface plasmon resonance,Indium molybdenum oxide,Optical fiber sensors,Wide wavelength tunability,Figure of merit,Sensitivity
更新于2025-09-04 15:30:14
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Effect of elastomer characteristics on fiber optic force sensing performance in biomedical robotics applications
摘要： Miniaturized and “smart” sensors are required for research in biology, physiology, and biomechanics, and they have extremely important clinical applications for diagnostics and minimally invasive surgery. Fiber optic sensors have been proven to provide advantages compared to conventional sensors and high potential for biomechanical and biomedical applications. They are small, easy to operate, minimally invasive with low risk, more accurate, and inexpensive. This paper reports the design and modeling of a fiber optic force sensor that is capable of measuring compliance for a contact force of up to 1 N. The main objective of this study is to design and model a fiber optic sensor capable of measuring the total force applied on an object. A polydimethylsiloxane (PDMS) elastomer film with a thickness of 1.2 mm is placed between an optical fiber tip and an object, and it is used for measuring the force applied on a rigid element. The compliance of the fiber optic force sensor is measured by recording the response of PDMS elastomer films under different load conditions. We use finite element modeling results as a basis for comparing experimental data. The agreement between theoretical predictions and experimental data is reasonable and within an acceptable range.
关键词： Force sensor,FEM analysis,Optical fiber,Elastomer,MATLAB analysis,LabVIEW,ANSYS simulation,Biomedical robotics
更新于2025-09-04 15:30:14