- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Athens, Greece (2018.7.4-2018.7.6)] 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Experimental Verification of the Optimum Diagonal Loading Level for Adaptive Matched Filtering with ?-OTDR System
摘要： Recently, a temporal adaptive matched filtering technique has been proposed to reduce the background noise in phase-sensitive optical time domain reflectometry (φ-OTDR) systems deployed for fibre optic distributed acoustic sensing (DAS) applications. This technique utilizes noise covariance matrix inversion which is estimated from signal-free assumed training samples. The detection performance degradation due to desired signal presence in the training data and the ill-conditioning of the matrix because of the limited training data are conventionally avoided by adding some amount of white noise on the diagonal elements of the covariance matrix. In this paper, the optimum level for this diagonal loading (DL) is investigated for DAS applications and verified with real φ-OTDR data. The optimum DL level which has been analytically proven in beamforming applications is shown to be applicable in the temporal domain noise filtering for DAS applications. The experimental results validate that the optimum DL value is negative.
关键词： diagonal loading,phase-sensitive optical time domain reflectometry (OTDR),distributed vibration sensors,optimum filtering.,Adaptive matched filter
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Oxidative segregation of Group V dopants in CdTe solar cells
摘要： Dual-pump driven, dispersion-synthesized parametric mixers have been identified as an efficient means for wavelength multicasting. In particular, four-mode phase-sensitive (PS) architecture, seeded by frequency-locked and phase-correlated four input optical signals, allows the parametric multicasting operated with ultralow noise and regenerative properties. To further corroborate the superiorities of the multimode PS operation, degenerate one- and three-mode PS parametric multicasting were numerically and experimentally compared, in terms of stability, phase manipulation, gain, and conversion efficiency, as well as noise performance.
关键词： wavelength multicasting,signal replication,One-mode phase-sensitive process,parametric mixer,three-mode phase-sensitive process
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Characterization of the Metallization Induced Recombination Losses in Industrial Silicon Solar Cells
摘要： We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum ampli?cation in phase-sensitive ampli?ers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) ampli?cation can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We ?nd that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS ampli?cation when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is suf?cient to achieve maximum PS ampli?cation of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent ampli?cation by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
关键词： parametric ampli?ers,Optical ?ber communication,phase-sensitive ampli?ers (PSAs),polarization
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Beijing, China (2019.11.21-2019.11.23)] 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Evaluation of Harmonic Voltage Emission Level Considering Harmonic Impedance of Photovoltaic Side
摘要： We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum ampli?cation in phase-sensitive ampli?ers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) ampli?cation can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We ?nd that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS ampli?cation when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is suf?cient to achieve maximum PS ampli?cation of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent ampli?cation by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
关键词： polarization,Optical ?ber communication,phase-sensitive ampli?ers (PSAs),parametric ampli?ers
更新于2025-09-23 15:21:01
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A hybrid distributed optical fibre sensor for acoustic and temperature fields reconstruction
摘要： We have proposed and experimentally demonstrated a distributed optical fibre sensor (DOFS) based on the hybrid of phase-sensitive optical time domain reflectometry (Ф-OTDR) and Raman optical time domain reflectometry (ROTDR), which could reconstruct the acoustic and temperature fields all along the sensing fibre at the same time. The Rayleigh back scattering (RBS), Raman Stokes (RS) and Raman anti-Stokes (RAS) generated by the probe pulse were separated by a WDM filter. Then the RBS was received by a heterodyne balanced photo detector (BPD) for quantitative vibration measurement and the dynamic acoustic field reconstruction, while the RS and RAS components were received directly by avalanche photodiodes (APDs) for temperature demodulation. The experimental results have shown that the proposed hybrid system could measure the temperature profile along a 12km long standard single-mode fibre with a maximal temperature uncertainty of 0.95℃ and a linearity response of R2=0.9986, along with a periodical knocking event detected simultaneously. Meanwhile, a 100Hz sinusoidal vibration at 12km distance along the same fibre could be clearly identified. Distributed knocking vibration and temperature was achieved at the same time with high accuracy.
关键词： temperature field,Distributed optical fibre sensors,acoustic field,Phase-sensitive OTDR (Ф-OTDR),Raman
更新于2025-09-23 15:21:01
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[Fundamental Biomedical Technologies] Advanced High-Resolution Tomography in Regenerative Medicine (Three-Dimensional Exploration into the Interactions between Tissues, Cells, and Biomaterials) || Introduction to X-Ray Micro-tomography
摘要： X-ray computed tomography (CT) represents one of the most powerful 3D non-destructive imaging techniques exploited in clinics to help the diagnostic process of many diseases. The progress achieved in the realization of detectors, in x-ray tube technology, and in the computational power of modern hardware has led to its translation toward micrometer and sub-micrometer range resolution applications. Micro-CT and nano-CT systems based on conventional micro-focus x-ray tubes or newest generation liquid-metal-jet anode (MetalJet) systems are, today, available and largely applied in biomedical research for in vitro studies of biomaterials, scaffolds, bones, teeth, etc. as well as for morphologic and functional studies on excised organs and small animals. Absorption-based imaging is the basis for the most common modality of CT scanners; however, the recent developments of x-ray sources based on synchrotron laboratories and capable to reach unprecedented characteristics of brilliance and intensity have allowed the implementation of innovative imaging approaches. These techniques exploit the refraction of x-rays in the matter instead of their absorption, overcoming the intrinsic limitation of conventional techniques and broadening the utility of micro-CT. In this chapter an overview of the basics of micro-CT will be given, starting from the sources characteristics, then describing the x-ray interactions with matter, and finally addressing the image formation principles. In this latter paragraph, particular attention will be reserved to phase-sensitive techniques, highlighting their potentials to improve biomedical research.
关键词： Nano-CT,Micro-CT,Phase-sensitive techniques,Biomedical imaging,X-ray computed tomography
更新于2025-09-23 15:21:01
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A Quantum Cascade Laser-Based Multi-Gas Sensor for Ambient Air Monitoring
摘要： A quantum cascade laser-based sensor for ambient air monitoring is presented and five gases, affecting the air quality, can be quantified. The light sources are selected to measure CO, NO, NO2, N2O and SO2. The footprint of the measurement setup is designed to fit in two standard 19” rack (48 cm × 65 cm) with 4 height units (18 cm) whereas one is holding the optical components and the other one contains the electronics and data processing unit. The concentrations of the individual analytes are measured using 2f-Wavelength Modulation Spectroscopy (2f-WMS) and a commercially available multipass gas cell defines the optical path. In addition, CO can also be measured with a dispersion-based technique, which allows one to cover a wider concentration range than 2f-WMS. The performance of this prototype has been evaluated in the lab and detection limits in the range of 1ppbv have been achieved. Finally, the applicability of this prototype for ambient air monitoring is shown in a five-week measurement campaign in cooperation with the Municipal Department for Environmental Protection (MA 22) of Vienna, Austria.
关键词： heterodyne phase sensitive dispersion spectroscopy,ambient air,infrared,quantum cascade laser,wavelength modulation spectroscopy
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Experimental Methods to Replicate Power Loss of PV Modules in the Field for the Purpose of Fault Detection Algorithm Development
摘要： Phase manipulation of four-mode phase-sensitive (4MPS) process was developed as a means for suppression of high-order four wave mixing (HoFWM) terms in dual-pump driven parametric wavelength multicasting and, consequently, for reduction of inter-channel crosstalk and inter-channel interference. In contrast to the previous studies that focused on power stabilization and conversion efficiency maximization, the investigation in this paper focuses on the evolution of the inter-channel HoFWM tones, whose suppression can be accomplished by arranging the phases of signals in a complementary manner. In addition, broadband 4MPS multicasting with suppressed HoFWM effects over 100-nm bandwidth, reaching up to 12-dB suppression ratio was demonstrated.
关键词： Four-mode phase-sensitive process,wavelength multicasting,inter-channel crosstalk,parametric mixer,inter-channel interference,four wave mixing
更新于2025-09-23 15:19:57
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Performance Optimization for Phase-Sensitive OTDR Sensing System Based on Multi-Spatial Resolution Analysis
摘要： This paper proposes and demonstrates a phase-sensitive optical time domain reflectometry (Φ-OTDR) sensing system with multi-spatial resolution (MSR) analysis property. With both theoretical analysis and an experiment, the qualitative relationship between spatial resolution (SR), signal-to-noise ratio (SNR) and the length of the vibration region has been revealed, which indicates that choosing a suitable SR to analyze the vibration event can effectively enhance the SNR of a sensing system. The proposed MSR sensing scheme offers a promising solution for the performance optimization of Φ-OTDR sensing systems, which can restore vibration events of different disturbance range with optimum SNR in merely a single measurement while maintaining the same detectable frequency range.
关键词： phase-sensitive optical time domain reflectometry (Φ-OTDR),signal-to-noise ratio (SNR),multi-spatial resolution (MSR) analysis
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Portland, OR, USA (2019.10.14-2019.10.16)] 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Optical Ground Network Diversity Analysis for Free Space Optical Communications
摘要： Dual-pump driven, dispersion-synthesized parametric mixers have been identified as an efficient means for wavelength multicasting. In particular, four-mode phase-sensitive (PS) architecture, seeded by frequency-locked and phase-correlated four input optical signals, allows the parametric multicasting operated with ultralow noise and regenerative properties. To further corroborate the superiorities of the multimode PS operation, degenerate one- and three-mode PS parametric multicasting were numerically and experimentally compared, in terms of stability, phase manipulation, gain, and conversion efficiency, as well as noise performance.
关键词： wavelength multicasting,signal replication,One-mode phase-sensitive process,parametric mixer,three-mode phase-sensitive process
更新于2025-09-19 17:13:59