- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Analysis of Seepage in a Laboratory Scaled Model using Passive Optical Fiber Distributed Temperature Sensor
摘要： Seepage is the key factor in the safety of dikes and earth‐fill dams. It is crucial to identify and localize the seepage excesses at the early stages before it initiates the internal erosion process in the structure. A proper seepage monitoring system should ensure a continuous and wide area seepage measurement. Here, continuous monitoring of seepage at the laboratory‐scale is achieved by a passive optical fiber Distributed Temperature Sensing (DTS) system. An experimental model was designed which consists of initially unsaturated sand model, water supply, seepage outflow, optical fiber DTS system, and water and air temperature measurement. Initially, the sand temperature was higher than the temperature of the seepage water. An optical fiber DTS system was employed with a high‐temperature resolution, short sampling intervals and short time intervals for temperature monitoring in the sand model. In the system, the small variation in the temperature due to groundwater flow was detected. The numerical analysis was conducted for both the seepage process and the heat transfer progression in the sand model. The results of the heat flow simulation were evaluated and compared with the measured temperature by the optical fiber DTS. Obvious temperature reduction was obtained due to seepage propagation in the sand. The rate of temperature reduction was observed to be dependent on the seepage flow velocity.
关键词： flow velocity,optical fiber DTS,temperature,seepage,saturation
更新于2025-09-23 15:19:57
-
[Lecture Notes in Electrical Engineering] Sensors and Microsystems Volume 629 (Proceedings of the 20th AISEM 2019 National Conference) || Relative Humidity Sensor Based on Tip of Multimode Optical Fiber Integrated with Photonic Crystal of Hydrogel Coated Polystyrene Nanoparticles
摘要： A relative humidity (RH) sensing device based on photonic crystal colloids auto-assembled directly on the tip of a multi-mode optical fiber is here described. The core-shell nanospheres are obtained by Polystyrene (PS) nanoporous structures (core) incorporated into a poly(N-isopropylacrylamide) (PNIPAM) hydrogel (shell) and are subsequently deposited via a vertical dip-coating technique on a multimode optical fiber tip. The sensing capability is due to the hydrogel shell that swells depending on the relative humidity that induce wavelength shift and amplitude changes in the photonic bandgap peak. Spectral characterization and sensing analysis are performed, and the obtained results show that spectral characteristics are highly non-linear and strongly manufacturing dependent. A resolution of 1% RH is measured at 30% RH that significantly decreases at higher RH. Hereby, numerical simulations based on the finite element method (FEM) have been performed in order to investigate the sensing mechanism.
关键词： Structural health monitoring,Deflection monitoring,Optical fiber sensors,Strain measurement
更新于2025-09-23 15:19:57
-
Recent Advances in Silica Glass Optical Fiber for Dosimetry Applications
摘要： In this paper, we review the highly promising silica glass, fabricated as doped and undoped optical fiber for intended use in radiation dosimetry. The dosimetry techniques reviewed here, underpinned by intrinsic and extrinsic defects in silica glass, focus on Thermoluminescence (TL), Optically Stimulated Luminescence (OSL) and Radioluminescence (RL), with occasional references to the much more established Radiation Induced Attenuation (RIA). The other focus in this review is on the various materials that have been reported earlier as dopants and modifiers used in silica glass optical fiber radiation dosimeters. This article also elaborates on recently reported optical fiber structures, namely, cylindrical fibers, photonic crystal fibers and flat fibers, as well as dimensions and shapes used for optimization of dosimeter performance. The various types of optical fiber radiation dosimeters are subsequently reviewed for various applications ranging from medical dosimetry such as in external beam radiotherapy, brachytherapy and diagnostic imaging, as well as in industrial processing and space dosimetry covering a dynamic dose range from μGy to kGy. Investigated dosimetric characteristics include reproducibility, fading, dose response, reciprocity between luminescence yield to dose-rate and energy dependence. The review is completed by a brief discussion on limitations and future developments in optical fiber radiation dosimetry.
关键词： radioluminescence,thermoluminescence,Silica optical fiber,review,dosimetry
更新于2025-09-23 15:19:57
-
[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - 2 ??m Thulium-doped Fiber Laser Based on Synchronously Pumped Mode-locking
摘要： Mobile fronthaul is an important network segment that bridges wireless baseband units and remote radio units to support cloud radio access network. We review recent progresses on the use of frequency-division multiplexing to achieve highly bandwidth-efficient mobile fronthaul with low latency. We present digital signal processing (DSP) techniques for channel aggregation and deaggregation, frequency-domain windowing, adjacent channel leakage ratio reduction, and synchronous transmission of both the I/Q waveforms of wireless signals and the control words (CWs) used for control and management purposes. In a proof-of-concept experiment, we demonstrate the transmission of 48 20-MHz LTE signals with a common public radio interface (CPRI) equivalent data rate of 59 Gb/s, achieving a low round-trip DSP latency of <2 μs and a low mean error-vector magnitude (EVM) of ～2.5% after fiber transmission. In a follow-up experiment, we further demonstrate the transmission of 32 20-MHz LTE signals together with CPRI-compliant CWs, corresponding to a CPRI-equivalent data rate of 39.32 Gb/s, in single optical wavelength channel that requires an RF bandwidth of only ～1.6 GHz. After transmission over 5-km standard single-mode fiber, the CWs are recovered without error, while the LTE signals are recovered with an EVM of lower than 3%. Applying this technique to future 5G wireless networks with massive multiple-input multiple-output is also discussed. This efficient mobile fronthaul technique may find promising applications in future integrated fiber/wireless access networks to provide ultrabroadband access services.
关键词： fifth-generation (5G),common public radio interface (CPRI),Cloud radio access network (C-RAN),optical fiber transmission,mobile fronthaul,frequency-division multiplexing (FDM)
更新于2025-09-23 15:19:57
-
Introducing optical fiber as internal light source into direct absorption solar collector for enhancing photo-thermal conversion performance of MWCNT-H2O nanofluids
摘要： High-efficiency photo-thermal conversion is an attractive approach for solar thermal energy to alleviate energy crisis. In this work, MWCNT-H2O nanofluids were prepared and its photo-thermal conversion properties were characterized. Moreover, an optical fiber as internal light source was introduced into direct absorption solar collector (DASC), in which the photo-thermal conversion performance of the stored MWCNT-H2O nanofluids was systematically explored. The experimental results showed that the photo-thermal conversion performance of MWCNT-H2O nanofluids was improved by introducing optical fiber as internal light source into the DASC and a maximum photo-thermal conversion efficiency of 65.4% was acquired at the MWCNTs concentration of 0.010 wt.% and the optical fiber location of 15 mm. This study indicated that the MWCNT-H2O nanofluids applied in the DASC with optical fiber was a potential candidate for solar thermal energy.
关键词： direct absorption solar collector,nanofluids,optical fiber,Photo-thermal conversion
更新于2025-09-23 15:19:57
-
Sending-or-Not-Sending with Independent Lasers: Secure Twin-Field Quantum Key Distribution over 509??km
摘要： Twin-field (TF) quantum key distribution (QKD) promises high key rates over long distances to beat the rate-distance limit. Here, applying the sending-or-not-sending TF QKD protocol, we experimentally demonstrate a secure key distribution that breaks the absolute key-rate limit of repeaterless QKD over a 509-km-long ultralow loss optical fiber. Two independent lasers are used as sources with remote-frequency-locking technique over the 500-km fiber distance. Practical optical fibers are used as the optical path with appropriate noise filtering; and finite-key effects are considered in the key-rate analysis. The secure key rate obtained at 509 km is more than seven times higher than the relative bound of repeaterless QKD for the same detection loss. The achieved secure key rate is also higher than that of a traditional QKD protocol running with a perfect repeaterless QKD device, even for an infinite number of sent pulses. Our result shows that the protocol and technologies applied in this experiment enable TF QKD to achieve a high secure key rate over a long distribution distance, and is therefore practically useful for field implementation of intercity QKD.
关键词： remote-frequency-locking technique,repeaterless QKD,ultralow loss optical fiber,secure key distribution,Twin-field quantum key distribution
更新于2025-09-23 15:19:57
-
Monitoring of Strain and Temperature in an Open Pit Using Brillouin Distributed Optical Fiber Sensors
摘要： Marble quarries are quite dangerous environments in which rock falls may occur. As many workers operate in these sites, it is necessary to deal with the matter of safety at work, checking and monitoring the stability conditions of the rock mass. In this paper, some results of an innovative analysis method are shown. It is based on the combination of Distributed Optical Fiber Sensors (DOFS), digital photogrammetry through Unmanned Aerial Vehicle (UAV), topographic, and geotechnical monitoring systems. Although DOFS are currently widely used for studying infrastructures, buildings and landslides, their use in rock marble quarries represents an element of peculiarity. The complex morphologies and the intense temperature range that characterize this environment make this application original. The selected test site is the Lorano open pit which is located in the Apuan Alps (Italy); here, a monitoring system consisting of extensometers, crackmeters, clinometers and a Robotic Total Station has been operating since 2012. From DOFS measurements, strain and temperature values were obtained and validated with displacement data from topographic and geotechnical instruments. These results may provide useful fundamental indications about the rock mass stability for the safety at work and the long-term planning of mining activities.
关键词： temperature,brillouin shift frequency,geotechnical monitoring system,strain,robotic total station,marble quarry,distributed optical fiber sensors,unmanned aerial vehicle
更新于2025-09-23 15:19:57
-
New Optical Fiber Biosensor Method for Glucose in Serum
摘要： This paper presents the design and analysis of optical fiber biological sensor to measure and monitor the glucose ratio in blood samples. Simulations are carried out using Optisystem software to determine the optical power and mode for each sample. The sensing was accomplished by design Mach-Zehnder interferometer with using multimode fibers. The cladding of these fibers is stripped out of the fiber part. In addition, the wavelength of the light source has to be absorbable by the glucose in order to be detected. As a result, the refractive index (RI) of different serum glucose level has increased linearly by increasing the serum glucose level while the parameters of the RI step and the output power decreased linearly by increasing the RI of different serum glucose level. This result can be concluded as a new method for serum glucose level assessment.
关键词： optical fiber sensor,optisystem,MZI interferometer,biological sensor
更新于2025-09-23 15:19:57
-
Infrared radiation Induced attenuation of radiation sensitive optical fibers: influence of temperature and modal propagation
摘要： We investigate the X-ray (40 keV) and γ-ray (1.2 MeV) radiation responses of three different radiation sensitive Optical Fibers (OFs) up to 100 Gy(SiO2). In particular, we study the Radiation Induced Attenuation (RIA) in the Near Infrared domain (NIR) for single mode OFs doped with Phosphorus (P), Aluminum (Al) and Phosphorus/Cerium (PCe) in their cores at three temperatures up to 50 °C. RIA levels and kinetics strongly depend on the operating wavelength and fiber composition. For both P and PCe-doped fibers, the P1 defects are the main contributors to the RIA, with Ce-codoping inducing a decrease of radiation sensitivity. For the Al-doped fiber, no specific absorption bands can be discriminated in the NIR. Both X- and γ-rays lead to the same RIA levels and kinetics. The RIA spectral dependences on dose and temperature highlight the potential of the three investigated fibers for radiation detection and dosimetry. To better discuss the properties of point defects responsible for the NIR RIA, we analyze how the fundamental mode propagation influences the RIA spectra of each fiber type. By reasonably assuming that the core RIA exceeds largely the cladding RIA and by calculating the mode Confinement Factor (CF), the RIA spectra of the core material are reconstructed and the spectral characteristics of defects are discussed for each type of fibers.
关键词： Radiation Induced Attenuation,Aluminum,Optical fiber,Phosphorus,Cerium
更新于2025-09-23 15:19:57
-
Theoretical analysis on SPR based optical fiber refractive index sensor with resonance wavelength covering communication C+L band
摘要： Surface plasmon resonance (SPR) based optical fiber refractive index sensor with resonance wavelength covering communication C+L band with high sensitivity. When the thicknesses of MgO, TeO2 and TiO2 are set at 80nm, 45nm and 40nm respectively, the sensitivity are all larger than 9000nm/RIU, meanwhile the resonance wavelength covers communication C+L band(1530nm-1625nm).
关键词： Oxide,Optical fiber sensor,Sensitivity,Surface plasmon resonance (SPR),Communication C+L band
更新于2025-09-23 15:19:57