- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Large-signal analysis based on nonlinear algebraic equations for an integrated photovoltaic modulea??converter system
摘要： Photovoltaic (PV) systems show nonlinear current–voltage characteristics that depend on both the temperature and the level of solar radiation. Impedance matching is required to achieve the optimal power transfer from such nonlinear PV systems under various temperatures and solar intensities. An efficient analysis method is proposed herein to obtain the characteristics of the PV panel and to simulate the whole system consisting of a PV panel and a converter. The aim is to enable large-signal analysis of an integrated photovoltaic module–converter system based on impedance matching. The Newton–Raphson method is used to obtain the solution of the nonlinear system of equations corresponding to a discrete equivalent circuit model. Various characteristics of the PV system and the simulation results for the whole system are obtained from the resulting linearized model.
关键词： Large-signal analysis,Impedance matching,Photovoltaic system,Converter
更新于2025-09-23 15:21:01
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Transmitter and Dispersion Eye Closure Quaternary (TDECQ) and its sensitivity to impairments in PAM4 waveforms
摘要： This paper presents the principles behind the transmitter and dispersion eye closure quaternary (TDECQ) test. A novel method to decompose TDECQ values is proposed where the result is separated into penalties from signal impairments that are either equalizable or non-equalizable by the reference receiver, enabling a more comprehensive study of signal quality. Moreover, the impact of selected impairments is studied in terms of their TDECQ penalty and its composition. This is achieved by producing generic test signals, where isolated impairments are applied to a high quality reference signal. The impairments include low-pass filtering, amplitude noise, compression and eye skew. Low-pass filtering is shown to contribute mainly to increase the equalizable penalty while noise, compression and eye skew are shown to affect mainly the non-equalizable part. The results serve as a generic guideline to understand the engineering rules and parameter limits that are needed to design links using TDECQ.
关键词： Physical Layer,system validation,pulse modulation,signal analysis,Optical fiber communication
更新于2025-09-23 15:21:01
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Large signal analysis of multiple quantum well transistor laser: Investigation of imbalanced carrier and photon density distribution
摘要： In this paper, we present a large-signal and switching analysis for the Heterojunction Bipolar Transistor Laser (HBTL) to reveal its optical and electrical behavior under high current injection conditions. Utilizing appropriate models for carrier transport, nonlinear optical gain, and optical confinement factor, we have simulated the large-signal response of the HBTL in relatively low and high modulation frequencies. Our results predict that for multiple quantum well (MQW) structures at low frequencies, there should not be a difference in either the carrier density or the photon density. However, the carrier concentration can be differently distributed between subsequent wells in the case of a high speed yet large-signal input. This leads to increased linewidth instead as it depends on ΔNqw. We show the effect of different structural parameters on the switching behavior by performing a switching analysis of the single quantum well and MQW structures using computationally efficient numerical methods. A set of coupled rate equations are solved to investigate the large-signal and switching behavior of MQW-HBTL. Finally, to have a comprehensive judgment about this optoelectronic device, we introduce a relative performance factor taking into account all the optoelectronic characteristics such as the output power, ac current gain, modulation bandwidth, and base threshold current, as well as turn-on time in order to design a suitable TL for optoelectronic integrated circuits.
关键词： multiple quantum well,switching analysis,carrier density,Heterojunction Bipolar Transistor Laser,large-signal analysis,photon density
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Study on a Multi-channel Switchable and Environment Self-adaptive Ultrasonic Sensor in an Erbium-doped Fiber Ring Laser
摘要： The usefulness of the information contained in biomedical data relies heavily on the reliability and accuracy of the methods used for its extraction. The conventional assumptions of stationarity and autonomicity break down in the case of living systems because they are thermodynamically open, and thus constantly interacting with their environments. This leads to an inherent time-variability and results in highly nonlinear, time-dependent dynamics. The aim of signal analysis usually is to gain insight into the behavior of the system from which the signal originated. Here, a range of signal analysis methods is presented and applied to extract information about time-varying oscillatory modes and their interactions. Methods are discussed for the characterization of signals and their underlying nonautonomous dynamics, including time-frequency analysis, decomposition, coherence analysis and dynamical Bayesian inference to study interactions and coupling functions. They are illustrated by being applied to cardiovascular and EEG data. The recent introduction of chronotaxic systems provides a theoretical framework within which dynamical systems can have amplitudes and frequencies which are time-varying, yet remain stable, matching well the characteristics of life. We demonstrate that, when applied in the context of chronotaxic systems, the methods presented facilitate the accurate extraction of the system dynamics over many scales of time and space.
关键词： phase coherence,coupling function,Biomedical signal analysis,dynamical Bayesian inference,wavelet bispectrum,cardiovascular system,time-frequency analysis,brain dynamics,time-dependent dynamics
更新于2025-09-19 17:13:59
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - High Power Terahertz Source Based on Planar Antenna Integrated Vacuum Photodiode
摘要： The usefulness of the information contained in biomedical data relies heavily on the reliability and accuracy of the methods used for its extraction. The conventional assumptions of stationarity and autonomicity break down in the case of living systems because they are thermodynamically open, and thus constantly interacting with their environments. This leads to an inherent time-variability and results in highly nonlinear, time-dependent dynamics. The aim of signal analysis usually is to gain insight into the behavior of the system from which the signal originated. Here, a range of signal analysis methods is presented and applied to extract information about time-varying oscillatory modes and their interactions. Methods are discussed for the characterization of signals and their underlying nonautonomous dynamics, including time-frequency analysis, decomposition, coherence analysis and dynamical Bayesian inference to study interactions and coupling functions. They are illustrated by being applied to cardiovascular and EEG data. The recent introduction of chronotaxic systems provides a theoretical framework within which dynamical systems can have amplitudes and frequencies which are time-varying, yet remain stable, matching well the characteristics of life. We demonstrate that, when applied in the context of chronotaxic systems, the methods presented facilitate the accurate extraction of the system dynamics over many scales of time and space.
关键词： phase coherence,coupling function,Biomedical signal analysis,dynamical Bayesian inference,wavelet bispectrum,cardiovascular system,time-frequency analysis,brain dynamics,time-dependent dynamics
更新于2025-09-19 17:13:59
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Graphite lithiation and capacity fade monitoring of lithium ion batteries using optical fibers
摘要： Increasing the e?ciency and safety of battery management systems may require internal monitoring of lithium ion batteries. In this work, we present an analysis of the interaction between ?ber-optic evanescent wave sensors (FOEWS) and graphite particles within a lithium ion battery over multiple cycles. Through slow charging and long rest periods, the FOEWS signal has shown sensitivity to lithium concentration at the surface of graphite particles by demonstrating a response to the slow di?usion of lithium ions within graphite particles during rest periods (i.e. relaxation of the electrode). The slope of the FOEWS signal during a full charge is found to exhibit three distinct peaks that occur within lithiated graphite's stage transitions zones IV, III and II. Deviation from the observed three peak trend correlates with signi?cant battery capacity fade and thus indicate the sensors ability to detect capacity fade in real-time. During experiments, signi?cant deviations in the slope during charging occurred at about ~5% SOC and minor disturbances to the slope were observed at ~80% SOC, which supports limiting the depth of charge and discharge to avoid accelerated capacity fade. These results deepen our understanding of the FOEWS's interaction with lithium ion batteries and supports the development of algorithms that optimize the control and monitoring of graphite lithiation with the aim of achieving safer operation as well as maximizing capacity and battery life.
关键词： Optical ?ber sensor,Lithium ion battery,State of charge,Graphite,Capacity fade,Signal analysis
更新于2025-09-19 17:13:59
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[OSA Optical Fiber Sensors - Lausanne (2018..-..)] 26th International Conference on Optical Fiber Sensors - Towards a Single Parameter Sensing for Bacteria Sorting through Optical Fiber Trapping and Back-Scattered Signal Analysis
摘要： We investigated if a recently proposed method can differentiate yogurt bacteria trapped by a polymeric lensed fiber tip, through back-scattered signal analysis. Results suggest that it can be a valuable contribution for foodborne analysis/bacteria identification.
关键词： optical fiber trapping,foodborne analysis,bacteria sorting,back-scattered signal analysis
更新于2025-09-16 10:30:52
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Nonlinear Optics - Novel Results in Theory and Applications || Nonlinear Schr?dinger Equation
摘要： Firstly, based on the small-signal analysis theory, the nonlinear Schrodinger equation (NLSE) with fiber loss is solved. It is also adapted to the NLSE with the high-order dispersion terms. Furthermore, a general theory on cross-phase modulation (XPM) intensity fluctuation which adapted to all kinds of modulation formats (continuous wave, non-return-to-zero wave, and return-zero pulse wave) is presented. Secondly, by the Green function method, the NLSE is directly solved in the time domain. It does not bring any spurious effect compared with the split-step method in which the step size has to be carefully controlled. Additionally, the fourth-order dispersion coefficient of fibers can be estimated by the Green function solution of NLSE. The fourth-order dispersion coefficient varies with distance slightly and is about 0.002 ps4/km, 0.003 ps4/nm, and 0.00032 ps4/nm for SMF, NZDSF, and DCF, respectively. In the zero-dispersion regime, the higher-order nonlinear effect (higher than self-steepening) has a strong impact on the short pulse shape, but this effect degrades rapidly with the increase of β2. Finally, based on the traveling wave solution of NLSE for ASE noise, the probability density function of ASE by solving the Fokker-Planck equation including the dispersion effect is presented.
关键词： small-signal analysis,traveling wave solution,Fokker-Planck equation,Green function,nonlinear Schrodinger equation
更新于2025-09-12 10:27:22
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Signal analysis and processing method of transmission optical fiber hydrogen sensors with multi-layer Pd–Y alloy films
摘要： To detect hydrogen leakage as soon as possible, researchers try their best to improve the sensitivity and response speed of the hydrogen sensor. However, the sensitivity and response speed are two contradictive parameters. It is hard to improve them simultaneously. The transmission optical fiber sensor with multi-layer films is the only structure which can increase the response speed and enhance sensibility simultaneously. However, because of its special structure, the output signal of the sensor often drifts. This paper designed an in-situ observation system to study the reason why the sensor drifts. The in-situ observation system found a periodic oscillation pattern for the transmission spectrum which depends on the wavelength of the light source. The transmission spectrum patterns of the sensor with multi-layer PalladiumeYttrium (PdeY) alloy films under different hydrogen concentrations were analyzed. The source of drift error induced by the wavelength shift of the light source was confirmed. By using a moving average algorithm, the error characteristics of the sensor were analyzed and simulated. The results show that the increased sweep width of the laser can effectively restrain the signal drift of sensors. Particularly, when the sweep width of the laser just is the integer multiples of the period of the transmission spectrum, the suppression of the oscillation was optimal. A sensor with a wavelength-swept laser was implemented. For the sweep width of 1.1 nm, the maximum wavelength sensitivity of the sensor is only 0.046 mv/pm. The wavelength drift error is significantly less than that without signal processing. The sensor has achieved a detection limit of 0.05% which is identical to the sensor with the frequency-stabilized laser. Finally, a design principle was proposed to optimize the light source parameters and structure parameters of the probe for the high stability of the optical fiber hydrogen sensor.
关键词： Stability design,Optical fiber hydrogen sensor,Signal analysis and processing
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Long Length Fibre Fabry-Perot Interferometers and their Applications in Fibre Characterization and Temperature Sensing
摘要： Since the free spectral range (FSR) of a fibre Fabry-Perot (f-FP) is the reciprocal of the time delay inside the interferometer, it can be used for the precise measurement of fibre properties (chromatic dispersion when measured as a function of wavelength, birefringence, etc.) or for the measurement of environmental changes (such as temperature, pressure, stress, etc.) which alter the fibre’s parameters. Here we propose a method to precisely measure the FSR of long-length f-FP based on an incoherent optical source and RF beat signal analysis. We built a 7-m long f-FP made of a single mode fibre (SMF) and investigated the use of several algorithms to evaluate the FSR. When measuring over time, we achieved an excellent accuracy down to 2.4 Hz (corresponding to a relative error of 1.5× 10??). To demonstrate its use in sensing application, we varied the f-FP temperature and monitored the associated FSR. We achieved a sensitivity of 345 Hz/K, leading to an excellent temperature resolution below 10 mK. Additionally, the achieved high accuracy in the measured FSR can also be used to measure fibre’s properties very precisely (e.g., zero chromatic dispersion wavelength) or to determine their temperature dependence. The method requires no alignment and requires only a few off-the-shelf components and instruments.
关键词： fibre characterization,temperature sensing,RF beat signal analysis,free spectral range,fibre Fabry-Perot interferometers
更新于2025-09-12 10:27:22