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- 2019
- time delay
- fiber Bragg grating
- microwave photonics
- finite impulse response
- Fourier transform
- optical sensors
- Optoelectronic Information Science and Engineering
- Southern University of Science and Technology
- University of Kent
- University of Kent, Tianjin Normal University
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Nonuniform Microwave Photonic Delay-Line Filter For Optical Sensor Network Interrogation
摘要： We propose a new design of nonuniform spaced microwave photonic delay-line filter based generic optical fiber sensors interrogation platform. Both the amplitude and phase response of the microwave filter are used to demodulate optical sensors. Therefore, a large sensor network with different types of optical sensors can be interrogated simultaneously. The concept of this new microwave photonics enabled interrogation approach is presented and verified by simulations where four different types of optical sensors are simultaneously interrogated via inverse Fourier transform of filter frequency response.
关键词： time delay,fiber Bragg grating,microwave photonics,finite impulse response,Fourier transform,optical sensors
更新于2025-09-11 14:15:04
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Demonstration of a Sub-GHz flat-top RF-Photonic Filter Enabled by Fourth-order Dispersion Compensation
摘要： We demonstrate a sub-GHz RF-photonic filter based on phase and amplitude control of a wideband all-fiber frequency parametric comb with 25-GHz tone spacing. The narrow bandwidth filter construction based on 221 comb tones was enabled by fourth-order dispersion compensation of the dispersive element. The filter integrity was further tested by retrieval of a set of digital modulated RF channels.
关键词： Chromatic dispersion,Microwave photonics,Optical signal processing,Finite impulse response filters
更新于2025-09-11 14:15:04
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[IEEE 2018 11th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) - Budapest (2018.7.18-2018.7.20)] 2018 11th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) - Spatial Interpolation of Optical Wireless Impulse Responses
摘要： In this paper, spatial interpolation is proposed as a time-saving technique for the estimation of the different Optical Wireless Impulse Responses which result from the nodes’ position changes in the mobility modeling of wireless optical communications. Typically, in this kind of analysis, the time-dependent impulse response is calculated numerically at each point of the path. However, this approach may result prohibitive due to the computation time. In this work, a support domain distributed on the moving area is defined, and accurate impulse responses for the domain’s points are obtained using a Monte Carlo Ray Tracing algorithm. Then, using this support, Lagrange interpolation method is applied for quick calculation out-of-the-support positions’ impulse responses. In this way, the impulse response for those points included in nodes’ path can be obtained without a high time and computational cost. The Lagrange interpolants were essayed with successful results, suggesting that the proposed technique may become relevant in upcoming statistical modeling in mobility situations.
关键词： Spatial Interpolation,Impulse Response,Lagrange Interpolation,Monte Carlo Ray Tracing,Optical Wireless Communication
更新于2025-09-11 14:15:04
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Study on the Frequency Bandwidth Limits for Deconvolution of the Step Response
摘要： A non-ideal step response of the digitizer may introduce significant errors in the impulse voltage measurement. Deconvolution is a good method to correct the step response. However, it is sensitive to noise. We studied on the influence of the frequency bandwidth limit on the deconvolution processing, with the results reported in this paper. This correction method was applied to the step responses recorded with three different commercial digitizers, and the error introduced by the corrected step responses were all reduced to less than 0.1%, which would be negligible in the impulse measurement.
关键词： digitizer,lightning impulse,step response,impulse response,deconvolution,impulse signal,convolution
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Reference System for the Practical Peak Voltage Calibration in Radiology and Diagnostic Applications
摘要： Practical Peak Voltage (PPV) has been recently adopted by IEC as a new quantity to qualify the pulsed voltages applied to X-ray high voltage tubes. Two commercial invasive dividers are characterized for every x-ray pulses for voltage up to 150 kV and for exposure time between 200 μs and few seconds. The measurement of impulse low current flowing through X-ray tubes is carried out non-invasively by using a clamp meter based on Hall Effect. Deconvolution technique is used to enhance the accuracy of the reference system.
关键词： Radiology,step response,X-ray,Switching impulse,Inverse FFT,Lightning impulse,High voltage,deconvolution,Clamp meter,convolution,FFT
更新于2025-09-10 09:29:36
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A New Analytical Charge Transfer Model for Time-of-Flight Image Sensors
摘要： A powerful tool for analyzing the performances of an image sensor designed for time-of-flight measurement purposes, the impulse response measurement (IRM), is presented. A way to measure the charges diffusion time (time for the photogenerated charges to be collected by the photodiode) using the analysis of an IRM is given. An unexpected phenomenon that occurs when performing a specific IRM is then showcased: performing two successive transfers, a short duration one followed by a long duration one is actually less efficient than performing a single transfer of long duration (same duration as the second transfer in the first case). Accordingly, a mathematical sufficient condition on the charge transfer efficiency function (CTEF) is enounced. A physical modeling based on thermionic emission theory and the influence of the potential barrier’s width on its effective height is presented. The model leads to a new CTEF expression that fulfills the mathematical requirement. Finally, a numerical simulation with the new CTEF fitting the experimental IRM data is performed.
关键词： time-of-flight (TOF),thermionic emission theory,Dirac-light pulse (DLP),diffusion time,impulse response measurement (IRM),Charge transfer efficiency function (CTEF),CMOS image sensor (CIS),light image detection and ranging (LIDAR),sense node (SN)
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Effect of Coaxial Cables on Measurements Performed with Resistive Lightning Impulse Voltage Dividers
摘要： The effect of the coaxial cable type and length on the lightning impulse parameters is often neglected. However, studies have shown that the coaxial cable length can affect the parameters that are calculated according to IEC 60060-1:2010. This study investigates how different coaxial cables influence the impulse waveforms by measuring the input and output of the cable under test with a 2-channel digitizer. Non-standard lightning impulses were generated using an impulse voltage calibrator. Results indicate that coaxial cables attenuate the test voltage and increase both the front time and time-to-half value.
关键词： measurement,measurement uncertainty,measurement techniques,Calibration,impulse testing
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Effect of Step Response Measurement Arrangement on the Correction of Lightning Impulses Measured with Ultra-High-Voltage Dividers
摘要： Ultra-high-voltage (UHV) lightning impulse voltage dividers normally have limited bandwidth, which deforms the waveform of the measured impulse. The step response of the dividers can be used to correct the measured waveforms by de-convolution, reducing the errors of the impulse parameters. The circuit arrangement for measuring step response, however, may influence the measured step response and the corrected impulse waveforms. In this paper, two circuit arrangements of step response measurement were used in investigating the effect of different step responses on the corrected impulses. The lightning impulses measured using two UHV dividers were corrected and the errors of the impulse parameters before and after correction were determined. The results show that accurate correction can be made for the dividers without being affected by the external connection arrangement of the step response measurement.
关键词： step response,ultra-high-voltage divider,Impulse high-voltage,de-convolution
更新于2025-09-10 09:29:36
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Photo-electrochemical stability of copper oxide photocathodes deposited by reactive high power impulse magnetron sputtering
摘要： Copper oxide thin films were deposited by a reactive high power impulse magnetron sputtering (r-HIPIMS) on glass substrates with a SnO2:F (FTO) layer. The pulse magnetron discharge was analyzed via the radio frequency (RF) Sobolewski probe, used for the time-resolved measurement of ion flux density on the substrate. Pulsed discharge current and voltage waveforms were analyzed. It was found that the pulse magnetron discharge worked in a self-sputtering mode with a stable or slightly growing discharge current after pulse discharge stabilization. As-deposited copper oxide films exhibited a certain degree of crystallinity, as identified by XRD, which was further improved after postdeposition annealing at 550 oC in the air. After annealing, the mixture of CuO and Cu2O crystallites was usually found in the films and in a few cases CuO0.96 phase was detected. Deposited films exhibited a p-type conductivity and relatively high photocurrents in the cathodic region after the postdeposition annealing. The highest photocurrent density of ip ≈ 1.1 mA cm-2 at potential -500 mV vs. Ag/AgCl was detected for films with a thickness of 1200 nm.
关键词： magnetron discharge,photocurrent,high power impulse magnetron sputtering,reactive sputtering,copper oxide,photocathode
更新于2025-09-10 09:29:36
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Optical sectioning with a Wiener-like filter in Fourier integral imaging microscopy
摘要： Non-scanning, single-shot, 3D integral microscopy with optical sectioning is presented. The method is based on the combination of Fourier-mode integral microscopy with a 3D deconvolution technique. Specifically, the refocused volume provided by a regular back-projection algorithm is 3D deconvolved with a synthetic 3D impulse response function that takes into account the number and positions of the elemental images. The use of this hybrid technique provides a stack of true-color depth-refocused images with significant gain of optical sectioning. The stack can be used, among other applications, to inspect inside the thick microscope specimen, to calculate collections of perspective views with fine angular resolution and extended full parallax, and also to display 3D images in an integral monitor. The method here presented is validated with both simulation and experimental data.
关键词： Fourier-mode integral microscopy,optical sectioning,3D integral microscopy,3D deconvolution,synthetic 3D impulse response function
更新于2025-09-10 09:29:36