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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - A wavelength swept laser-based demodulation method for long-distance fiber Bragg grating sensing
摘要： A novel long distance fiber Bragg grating (FBG) demodulation scheme which can eliminate the influence of Rayleigh scattering is proposed. It can detect changes of FBG reflection wavelengths 100km away with an accuracy about 20 pm.
关键词： Rayleigh scattering,FBG demodulation,wavelength measurement,Long distance sensing
更新于2025-09-11 14:15:04
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Experimental and Theoretical Research on Bending Behavior of Photovoltaic Panels with a Special Boundary Condition
摘要： Currently, the photovoltaic (PV) panels widely manufactured on market are composed of stiff front and back layers and the solar cells embedded in a soft polymeric interlayer. The wind and snow pressure are the usual loads to which working PV panels need to face, and it needs the panels keep undamaged under those pressure when they generate electricity. Therefore, an accurate and systematic research on bending behavior of PV panels is important and necessary. In this paper, classical lamination theory (CLT) considering soft interlayer is applied to build governing equations of the solar panel. A Rayleigh–Rita method is modified to solve the governing equations and calculate the static deformation of the PV panel. Different from many previous researches only analyzing simply supported boundary condition for four edges, a special boundary condition which consists of two opposite edges simply supported and the others two free is studied in this paper. A closed form solution is derived out and used to do the numerical calculation. The corresponding bending experiments of PV panels are completed. Comparing the numerical results with experiment results, the accuracy of the analytical solutions are verified.
关键词： bending behavior,classical lamination theory,bending experiment,photovoltaic panel,Rayleigh–Rita method,special boundary condition
更新于2025-09-11 14:15:04
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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) - Optimum Mitigation of distortion induced by Rayleigh Backscattering in Radio-over-Fiber links for the Square Kilometer Array Radio-Telescope
摘要： This paper presents theoretical and experimental study of unexpected distortions induced by the Rayleigh backscattering phenomenon in Radio-over-Fiber (RoF) links within the Square Kilometer Array (SKA) project. For this system, the radiofrequency (RF) signals coming from the sky and celestial sources are received by more than 130k antennas individually and then transmitted to the signal processing room through an analogue RoF link. The low frequency band considered (from 50MHz to 350MHz) and the relatively low levels of the power of such RF signals are identified as the cause of these distortion effects which can decrease drastically the receiver dynamic range. An analysis of the phenomenon is presented in this work, together with an efficient solution optimized for the considered applicative case.
关键词： Square Kilometer Array,Low Frequency Aperture Array,Radio-over-Fiber,Rayleigh Backscattering
更新于2025-09-11 14:15:04
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Tunable and large plasmonic field enhancement in core-shell heterodimer/trimer
摘要： Heterodimer/trimer are two/three closely adjacent nanoparticles dissimilar in shape or size, and represent a simple nanoscale geometry which gives rise to a remarkably rich set of properties. The core-shell nanostructure has advantages of tunability and stability over a similar homogeneous particle. We theoretically demonstrate tunable and significant field enhancement in both heterodimer and heterotrimer systems using core-shell geometry with a metal shell and dielectric core and compared our results with core-shell homodimer and homotrimer. The analytical modeling is based on the Rayleigh theory for small particles and Foldy–Lax multi-scattering theory for multiple particles. It is shown that the E-field can be enhanced in core-shell dimer/trimer due to the plasmonic resonance in the metal shell, which can be easily tunable by changing the core-shell ratio, composition of the core and shell, relative size and distance between the particles, and wavelength of the incident light. We report significant maximum field intensity enhancement near the particles. Moreover, this tunable nanostructures with high field intensity can be useful as potential bio-sensing applications.
关键词： tunability,Foldy–Lax theory,core-shell NPs,Heterotrimer,Rayleigh theory,plasmonic resonance
更新于2025-09-11 14:15:04
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Use of Same WDM Channels in Fiber Network for Bidirectional Free Space Optical Communication With Rayleigh Backscattering Interference Alleviation
摘要： In the paper, we present and demonstrate experimentally a 10 Gbit/s on-off keying (OOK) bidirectional wavelength-division-multiplexing (WDM) free space optical (FSO) communication architecture integrated in fiber network together with 5 m free space transmission length and 25 km fiber link, respectively. To achieve bidirectional FSO link, the all WDM wavelengths can be used simultaneously to serve as the downstream and upstream traffics in the proposed FSO-WDM system. Here, four pairs of line terminations (LTs) and optical wireless units (OWUs) are integrated arbitrarily in fiber access network for confidential and bidirectional FSO connection based on the requirement of practical environment. In the measurement, the relationship of FSO signal performance and detected tolerance are also discussed and analyzed. Moreover, the WDM-FSO transmission can also avoid the Rayleigh backscattering (RB) beat noise in fiber connection.
关键词： Free space optical communication,wavelength-division-multiplexing (WDM),Rayleigh backscattering (RB)
更新于2025-09-11 14:15:04
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Structural characterization determination of silicon nanocrystals embedded in amorphous silicon nitride matrix from the effect of the light scattering
摘要： In this work, we will study the elastic and inelastic light scattering by the silicon nanocrystals (Si-nc) embedded in amorphous silicon nitride matrix. Indeed, the photons are subjected to several modifications in terms of intensity, direction and wavelength when they interact with Si-ncs. The reflectance combined with photoluminescence (PL) and Raman spectroscopy are a very sensitive tool for probing the scattering light. Results show that the observed shift of the experimental PL peaks is attributed to the Raman scattering and the PL broadening peaks to the Rayleigh scattering. A novel method allowed the determination of both the core and the surface bond lengths of Si-nc was reported. The decrease of the Raman shift observed in structures containing Si-ncs is mainly due to the Si-nc curved surface, and it reflects the presence of silicon dangling bonds at the Si-nc interfaces.
关键词： Rayleigh scattering,Silicon nanocrystals,Silicon dangling bond,Raman scattering,Bond length,Silicon nanocrystal surface
更新于2025-09-10 09:29:36
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Micro Fabry-Pérot Interferometer at Rayleigh Range
摘要： The Fabry-Pérot interferometer is used in a variety of high-precision optical interferometry applications, such as gravitational wave detection. It is also used in various types of laser resonators to act as a narrow band filter. In addition, ultra-compact Fabry-Pérot interferometers are used in the optical resonators of semiconductor lasers and fiber-optic systems. In this work, we developed a micro-scale Fabry-Pérot interferometer that was constructed within the Rayleigh range of the optical focusing system. The high precision that is conventionally required for the optical parallelism and the surface accuracy of the mirrors was not so critical for this type of Fabry-Pérot interferometer. The interferometer was constructed using a gold-coated silicon microcantilever with reflectivity of 92% and a dielectric multilayer flat mirror with reflectivity of 85%. The focal spot size of the laser beam is 20 μm and the cavity length is approximately 20 μm. The finesse was measured to be approximately 25. The interferometric characteristics of the device were consistent with the theoretically calculated performance. The developed micro Fabry-Pérot interferometer has the potential to make a marked contribution to advances in optical measurements in various micro sensing system.
关键词： microcantilever,Rayleigh range,optical measurements,optical interferometry,Fabry-Pérot interferometer
更新于2025-09-10 09:29:36
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Radiation-induced loss of silica optical fibres with fluorine-doped cladding
摘要： The effect of gamma-irradiation of the fluorine-doped silica depressed cladding graded-index fibre (DCGIF) has been researched. New mechanism of the non-bridging oxygen hole centers (NBOHC) defect formation, conditioned by different mobility of diffusion counter flows of fluorine and oxygen at the core-cladding interface, has been proposed. Using silica tubes with 0.02 wt% of OH groups and hydrogen in free state in MCVD-technology of DCGIF fabrication completely eliminates the NBOHC absorption at the wavelength of 630 nm. However, gamma-irradiation of such fibres results in anomalously high attenuation level in the visible range of optical spectrum. It was established that irradiation of DCGIF leads to light scattering which is probably due to the appearance of optical inhomogeneities in the glass matrix.
关键词： fibre optics,Rayleigh scattering,fibre design and fabrication,radiation-resistant optical fibres
更新于2025-09-09 09:28:46
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Hyperspectral Terahertz Tomography in Amplitude Contrast
摘要： Hyperspectral Terahertz Tomography in amplitude contrast is presented using a time-domain spectroscopy system in the spectral range 0.3 - 2.5 THz. The Fourier transformed signal data is used to reconstruct test objects’ cross-sections at multiple frequencies using standard filtered backprojection. The full hyperspectral set of images reconstructed at around 300 adjacent spectral points is used to trace the combined contribution of Beer-Lambert volume attenuation, Fresnel reflection losses and Rayleigh roughness scattering losses, which is in good overall agreement with the experimental results. The image quality for Styrofoam (refractive index around 1.02, attenuation coefficient < 1 mm-1) test objects is best in the range 0.8 - 2.0 THz depending on the porosity of the material.
关键词： THz,time-domain spectroscopy,hyperspectral imaging,Rayleigh roughness,hard-field tomography
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Radar Forward-Looking Superresolution Imaging for SEA-Surface Targets Using Bayesian Method
摘要： This paper presents an angular superresolution method based on maximum a posterior (MAP) criterion to improve the azimuthal resolution of forward-looking scanning radar in the background of sea clutter. Firstly, in consideration of the statistical property of sea clutter, the Rayleigh distribution is employed to express the likelihood function. And then, the generalized Gaussian constraint is used as prior information about targets for better property of noise suppression and positional accuracy. Finally, the iterative expression is derived to recover the scattering coefficient of original sea-surface targets. Compared to the conventional Bayesian approaches, The results of simulation experiment are given to verify the superior performance of proposed method.
关键词： forward-looking,scanning radar imaging,generalized Gaussian prior,Rayleigh distribution
更新于2025-09-09 09:28:46