- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A Distortion Model of Laser Sheet for a Laser Line Scanner with Large Fan Angle
摘要： Single carrier frequency domain equalization (SC-FDE) is an alternative technology to orthogonal frequency division multiplexing to deal with the frequency selective channel fading effect in broadband wireless communication systems. In this paper, we consider a robust SC-FDE design with imperfect channel knowledge at a receiver due to the channel estimation error. Based on a statistical model for channel estimation, the optimal equalization coefficients are derived under the criterion of minimizing the mean square error conditioned on a given channel estimate. The bit error rate is further analyzed and a tight performance approximation is proposed. We also propose two robust FDE schemes in coded systems, where feedback from the channel decoder is utilized to improve the equalization and/or channel estimation performance. Simulation results show that the proposed robust FDE schemes achieve significant performance improvement over the conventional FDE schemes.
关键词： robust frequency domain equalization,noise predictor,Imperfect channel knowledge
更新于2025-09-16 10:30:52
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Orbital angular momentum holography for high-security encryption
摘要： Holography has been identified as a vital platform for three-dimensional displays, optical encryption, microscopy and artificial intelligence through different physical dimensions. However, unlike the wavelength and polarization divisions, orbital angular momentum (OAM) of light, despite its helical wavefront being an independent physical dimension, has not been implemented as an information carrier for holography due to the lack of helical mode index selectivity in the Bragg diffraction formula. Here, we demonstrate OAM holography by discovering strong OAM selectivity in the spatial-frequency domain without a theoretical helical mode index limit. As such, OAM holography allows the multiplexing of a wide range of OAM-dependent holographic images with a helical mode index spanning from ?50 to 50, leading to a 10?bit OAM-encoded hologram for high-security optical encryption. Our results showing up to 210 OAM-dependent distinctive holographic images mark a new path to achieving ultrahigh-capacity holographic information systems harnessing the previously inaccessible OAM division.
关键词： optical encryption,orbital angular momentum,spatial-frequency domain,high-security encryption,holography
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Auckland, New Zealand (2019.5.20-2019.5.23)] 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - High-Spatial Resolution Demodulation of Weak FBGs Based on Incoherent Optical Frequency Domain Reflectometry Using a Chaotic laser
摘要： A high-spatial resolution demodulation technique based on incoherent optical frequency domain reflectometry is proposed for distributed weak fiber Bragg grating (FBG) sensing. A single longitudinal mode, narrow linewidth light output from Distributed Feedback Laser (DFB) is modulated with a frequency swept microwave, then enter the FBGs and reflected. The reflected optical signal is transformed into electric signal by a photodiode, and then mixes with the original microwave to produce the beat frequency. We can use Fast Fourier transformation to analyze the beat frequency to modulate the location information, next control the wavelength of DFB laser to sweep in a specific range and finally obtain the wavelength information of FBGs. In order to eliminate the influence of interference between light reflected from the FBGs, chaotic signals from DFB laser with optical feedback are generated to broaden the linewidth of laser. Therefore, the spatial resolution of FBGs can be greatly improved to 10cm. and we have demonstrated the long distance demodulation nearly 500m and 10cm interval with the achieved accuracy to be 16 pm.
关键词： high-spatial resolution,chaotic laser,narrow linewidth,Incoherent Optical Frequency Domain Reflection
更新于2025-09-12 10:27:22
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Comparison of diagnostic performance in assessing the rewiring position into a jailed side branch between online 3D reconstruction systems version 1.1 and 1.2 derived from optical frequency domain imaging
摘要： The three-dimensional reconstruction of optical coherence tomography and optical frequency domain imaging (3D-OCT/OFDI) helps optimize bifurcation percutaneous coronary interventions (PCIs) with side branch (SB) dilatation by identifying the optimal rewiring position. 3D-OCT/OFDI’s diagnostic performance for assessing the rewiring position into a jailed SB is unknown. We retrospectively evaluated the diagnostic performances of a conventional (ver. 1.1) and a new (ver. 1.2) online 3D-OFDI reconstruction system based on an offline 3D reconstruction system’s performance. We analyzed 45 patients’ 52 OFDI pullbacks with main vessel stenting followed by rewiring into a jailed SB for coronary bifurcation lesions. We counted the undetected stent struts in the polygon of confluence as the stent detection performance. We assessed the diagnostic agreement regarding the rewiring position into a jailed SB by the three 3D reconstruction systems. The percentage of undetected struts and the diagnostic agreement of ver.1.2 were significantly better than those of ver.1.1 [5.1 ± 5.1% vs. 30.2 ± 14.2%; p < 0.0001, and 94.2% (49/52) vs. 76.9% (40/52); p = 0.0120]. The new online 3D-OFDI reconstruction system provides better diagnostic performance than the conventional online system for assessing the rewiring position into a jailed SB.
关键词： Three-dimensional reconstruction,Agreement comparison,Coronary bifurcation stenting,Optical frequency domain imaging,Kissing balloon inflation
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) - Integrated Optical Fibre — Investigating the Vibrational Response using Optical Frequency Domain Reflectometry
摘要： Integrated Optical Fibre (IOF) is a new technology in integrated optics using flame hydrolysis deposition to permanently attach an optical fibre onto a silicon substrate. This approach combines the low losses of optical fibre with the mechanical integrity of an integrated planar platform. By attaching the fibre with high quality optical glass we create devices that transform the packaging of fibres for sensing applications removing any use of glues, epoxies, adhesives and making it suitable for harsh environments such as aerospace. The binding medium itself can also be used for its optical properties. Aerospace environments are demanding, both for temperature range (-50 to +120 °C), but also for vibration and shock. In this work we are investigating a technique for monitoring the vibration sensitivity and damage points of the IOF under typical structural vibration conditions. In particular, here we report the use of Optical Frequency Domain Reflectometry (OFDR), which can reveal spectral and spatial information of features within a fibre such as Fibre Bragg Gratings (FBGs). This is of particular interest when applied to structural health monitoring, distributed strain and temperature sensing.
关键词： Optical Frequency Domain Reflectometry,vibration sensitivity,structural health monitoring,Integrated Optical Fibre,Fibre Bragg Gratings
更新于2025-09-12 10:27:22
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[IEEE 2019 Second International Workshop on Mobile Terahertz Systems (IWMTS) - Bad Neuenahr, Germany (2019.7.1-2019.7.3)] 2019 Second International Workshop on Mobile Terahertz Systems (IWMTS) - Wideband Characterization of 3D Printed THz Rectangular Dielectric Waveguides by THz Frequency-Domain Spectroscopy
摘要： In this paper single-mode dielectric waveguides for 140 GHz are designed and fabricated by 3D printing technology. The waveguides are simulated using the finite difference time domain method and characterized by determining their frequency-dependent attenuation constant and frequency-dependent effective refractive index from 100 GHz to 180 GHz using THz frequency-domain spectroscopy. Furthermore, the mode patterns at different frequencies are observed by performing transversal scans of the far-field radiation pattern at the output of the waveguide.
关键词： Dielectric Waveguide,Frequency Domain Spectroscopy,THz
更新于2025-09-11 14:15:04
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Differential Electro-Optical Equivalent Circuit Model of a Vertical-Cavity Surface-Emitting Laser for Common-Mode Rejection Ratio Estimation
摘要： Vertical-cavity surface-emitting lasers (VCSEL) can be used to achieve galvanic isolation of systems operating in environments with high levels of electromagnetic noise. A small-signal differential electro-optical equivalent circuit model of a VCSEL is presented, in contrast to the usual single-ended models. The electro-optical and opto-electrical conversion of the signal is modelled, as well as the electrical characteristics of the VCSEL chip. The circuit model is based on an approach combining Y-parameters and mixed-mode S-parameters. Compared to conventional models that are aimed at describing the internal laser dynamics, the presented model is primarily focused on modelling the asymmetric parasitics in a differential VCSEL configuration. The parasitics between the 5-lead VCSEL TOSA package and the test printed circuit board are modelled. The impact of the asymmetry of the parasitics from the laser anode and cathode towards the ground is examined. The differential VCSEL model is used to estimate the transfer coefficients for both differential-mode and common-mode input signals. The ratio between the wanted and unwanted signal is expressed as the common-mode rejection ratio (CMRR). The model covers the frequency bandwidth up to 4 GHz required for integrated circuit EMC and ESD measurements.
关键词： lumped element model,laser diode,Electromagnetic compatibility,frequency domain characterization
更新于2025-09-11 14:15:04
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[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Graphene Multilayers for Quantum Microwave Signal Up-Conversion to the Optical Domain
摘要： We propose a new scheme for tunable quantum microwave signal upconversion to the optical frequency domain using graphene multilayers. The graphene layers are electrically connected, biased by a quantum level microwave signal, and subjected to intensive optical pump. The principle of operation is based on modifying the graphene conductivity by the biasing microwave signal. It then follows that an upper optical sideband is generated, while the lower sideband is resonantly attenuated by the destruction of the layered medium . Our calculations show large number of upconverted photons for microvolt driving microwave signal.
关键词： quantum microwave signal,graphene multilayers,optical frequency domain,upconversion
更新于2025-09-11 14:15:04
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Spectral super-resolution spectroscopy using a random laser
摘要： Super-resolution microscopy refers to a powerful set of imaging techniques that overcome the diffraction limit. Some of these techniques, the importance of which was recognized by the 2014 Nobel Prize for chemistry, are based on the concept of image reconstruction by spatially sparse sampling. Here, we introduce the concept of super-resolution spectroscopy based on sparse sampling in the frequency domain, and show that this can be naturally achieved using a random laser source. In its chaotic regime, the emission spectrum of a random laser features sharp spikes at uncorrelated frequencies that are sparsely distributed over the emission bandwidth. These narrow lasing modes probe stochastically the spectral response of a sample, allowing it to be reconstructed with a resolution exceeding that of the spectrometer. We envision that the proposed technique will inspire a new generation of simple, cheap, high-resolution spectroscopy tools with a reduced footprint.
关键词： super-resolution spectroscopy,random laser,sparse sampling,spectral reconstruction,frequency domain
更新于2025-09-11 14:15:04
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Tunable Quantum Beat of Single Photons Enabled by Nonlinear Nanophotonics
摘要： We demonstrate the tunable quantum beat of single photons through the co-development of core nonlinear nanophotonic technologies for frequency-domain manipulation of quantum states in a common physical platform. Spontaneous four-wave mixing in a nonlinear resonator is used to produce nondegenerate, quantum-correlated photon pairs. One photon from each pair is then frequency shifted, without degradation of photon statistics, using four-wave-mixing Bragg scattering in a second nonlinear resonator. Fine tuning of the applied frequency shift enables tunable quantum interference of the two photons as they are impinged on a beam splitter, with an oscillating signature that depends on their frequency difference. Our work showcases the potential of nonlinear nanophotonic devices as a valuable resource for photonic quantum-information science.
关键词： four-wave-mixing Bragg scattering,nonlinear nanophotonics,frequency-domain manipulation,quantum interference,quantum states,quantum beat,single photons,photonic quantum-information science,quantum-correlated photon pairs,spontaneous four-wave mixing
更新于2025-09-11 14:15:04