- 标题
- 摘要
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- 实验方案
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Suppression of amplitude modulation induced by polarization mode dispersion using a multi-degree-of-freedom fiber filter
摘要： Polarization mode dispersion (PMD) in ?bers for high-power lasers can induce signi?cant frequency modulation to amplitude modulation (FM-to-AM) conversion. However, existing techniques are not suf?ciently ?exible to achieve ef?cient compensation for such FM-to-AM conversion. By analyzing the nonuniform transmission spectrum caused by PMD, we found that the large-scale envelope of the transmission spectrum has more serious impacts on the amount of AM. In order to suppress the PMD-induced FM-to-AM conversion, we propose a novel tunable spectral ?lter with multiple degrees of freedom based on a half-wave plate, a nematic liquid crystal, and an axis-rotated polarization-maintaining ?ber. Peak wavelength, free spectral range (FSR), and modulation depth of the ?lter are decoupled and can be controlled independently, which is veri?ed through both simulations and experiments. The ?lter is utilized to compensate for the PMD-induced FM-to-AM conversion in the front end of a high-power laser facility. The results indicate that, for a pulse with phase-modulation frequency of 22.82 GHz, the FM-to-AM conversion could be reduced from 18% to 3.2% within a short time and maintained below 6.5% for 3 h. The proposed ?lter is also promising for other applications that require ?exible spectral control such as high-speed channel selection in optical communication networks.
关键词： laser facility,laser systems,optimization,high-power laser,laser facility and engineering,advanced laser technology and applications,?ber laser and applications,modeling,design
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE SENSORS - Montreal, QC, Canada (2019.10.27-2019.10.30)] 2019 IEEE SENSORS - Industrial gas analytics using a compact ultraviolet laser
摘要： In this paper, we propose a simple, yet reliable methodology to expedite yield estimation and optimization of microwave structures. In our approach, the analysis of the entire response of the structure at hand (e.g., S-parameters as a function of frequency) is replaced by response surface modeling of suitably selected feature points. On the one hand, this is sufficient to determine whether a design satisfies given performance specifications. On the other, by exploiting the almost linear dependence of the feature points on the designable parameters of the structure, reliable yield estimates can be realized at low computational cost. Our methodology is verified using two examples of waveguide filters and one microstrip hairpin filter and compared with conventional Monte Carlo analysis based on repetitive electromagnetic simulations, as well as with statistical analysis exploiting linear response expansions around the nominal design. Finally, we perform yield-driven design optimizations on these filters.
关键词： microwave component modeling,yield-driven design,electromagnetic (EM) modeling,yield estimation,tolerance-aware design,Design centering,statistical analysis
更新于2025-09-23 15:19:57
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[IEEE 2020 5th International Conference on Devices, Circuits and Systems (ICDCS) - Coimbatore, India (2020.3.5-2020.3.6)] 2020 5th International Conference on Devices, Circuits and Systems (ICDCS) - Man of the League Algorithm Based Space Vector Modulated Inverter in Photovoltaic System
摘要： This paper proposes an ideal MLA based direct –current vector to control plot of GS-VSC. It is hold steady dc capacitor voltages to enhance the receptive power pay and to strengthen the converter straight adjustment limit.
关键词： Stimulator,Adaptive control,Power electronic,Design optimization methodology,DC-DC converters,Boost converter,Optimal design
更新于2025-09-23 15:19:57
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Optimal Design Methodology of Tapered Waveguide Transducers for Thickness Monitoring
摘要： For the purpose of providing transducers for long-term monitoring of wall thinning of critical pressure equipment in corrosion or high temperature environments, the optimal design methodology for tapered waveguide units was proposed in the present study. Firstly, the feasibility of the quasi-fundamental shear horizontal (SH0*) wave propagating in the tapered waveguide units was analyzed via numerical simulations, and the transmitting limitations of the non-dispersive SH0* wave were researched. Secondly, several tapered waveguide transducers with varying cross-sections to transmit pure SH0* wave were designed according to the numerical results. Experimental investigations were carried out, and the results were compared with waveguide transducers with a prismatic cross-section. It was found that the tapered waveguide units can transmit non-dispersive shear horizontal waves and suppress the wave attenuation at the same time. The experimental results agreed very well with the numerical simulations. Finally, high-temperature experiments were carried out, and the reliability of thickness measuring by the tapered waveguide transducers was validated. The errors between the measured and the true thicknesses were small. This work paves a solid foundation for the optimal design of tapered waveguide transducers for thickness monitoring of equipment in harsh environments.
关键词： optimal design,quasi-fundamental shear horizontal wave,structural health monitoring,tapered waveguide unit,harsh environment
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) - Advanced Characterisation of Black Silicon Surface Topography with 3D PFIB-SEM
摘要： Modeling complex natural and human systems to support policy or management decision making is becoming increasingly common. The resulting models are often designed and implemented by researchers or domain experts with limited software engineering expertise. To help this important audience, we present our experience and share lessons learned from the design and implementation of an agent-based model of agricultural production systems in the Argentine Pampas, emphasizing the software engineering perspective. We discuss the model’s design including the model classes; the activity diagram, and data flow; the package and folder layout; the use of design patterns; performance optimization; initialization approaches; the analysis of results; and model measurement, validation, and verification.
关键词： agent-based modeling,coupled human and natural systems,Complex adaptive systems,software engineering,model design and implementation
更新于2025-09-23 15:19:57
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Production Tools Made by Additive Manufacturing Through Laser-based Powder Bed Fusion; Herstellung von Produktionswerkzeugen mittels additiver Fertigung durch laserbasiertes Pulverbettschmelzen;
摘要： This paper deals with the design and production of stamping tools and dies for sheet metal components and injection molds for plastic components. Laser-based Powder Bed Fusion (LPBF) is the additive manufacturing method used in this investigation. Solid and topology optimized stamping tools and dies 3D-printed in DIN 1.2709 (maraging steel) by LPBF are approved/certified for stamping of up to 2-mm thick hot-dip galvanized DP600 (dual-phase steel sheet). The punch in a working station in a progressive die used for stamping of 1-mm thick hot-dip galvanized DP600 is 3D-printed in DIN 1.2709, both with a honeycomb inner structure and after topology optimization, with successful results. 3D printing results in a significant lead time reduction and improved tool material efficiency. The cost of 3D-printed stamping tools and dies is higher than the cost of those made conventionally. The core (inserts) of an injection mold is 3D-printed in DIN 1.2709, conformal cooling optimized and 3D-printed in Uddeholm AM Corrax, and compared with the same core made conventionally. The cooling and cycle time can be improved, if the injection molding core (inserts) is optimized and 3D-printed in Uddeholm AM Corrax. This paper accounts for the results obtained in the above-mentioned investigations.
关键词： Design,Injection molding,Tools,Stamping,Powder bed fusion,Optimization,Topology,Metal,Additive manufacturing,Cooling
更新于2025-09-23 15:19:57
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Modelling and optimization of process parameters to obtain maximum tensile strength for laser butt welding of 316L austenitic stainless steel sheets
摘要： The attribute of high power density but low energy-input in Laser welding offers exciting solutions to the commonly encountered disadvantages with conventional joining techniques. In this paper, 316L Austenitic Stainless Steel metal sheets were butt welded using Nd:YAG Laser welding system. Owing to its low cost and specific properties such as excellent toughness, higher creep, stress to rupture at elevated temperatures, 316L A.S.S finds wide range of applications in the industrial arena especially in the automobile and marine sectors. Hence, it becomes imperative to examine its post weld properties after performing laser welding and find optimized values of the parameters. The prominent process parameters like Laser Power, Travel speed and Focal length were analysed and optimised. Design of experiment statistical tool was embraced for the systematic conduct of the tests. Response Surface Methodology (RSM) and analysis of variance (ANOVA) techniques were employed to identify the significant process parameters affecting the weld. An empherical relationship involving the parameters was developed to predict the ultimate tensile strength. The 3D response surface plot and contour plots were generated for this model to elucidate the interaction effect of Laser parameters (Travel speed and Focal length), (Laser Power and Focal Length) & (Laser Power and Travel Speed) on Ultimate Tensile Strength. The welded specimens cut by electric discharge machining were prepared for tensile testing as per the ASTM standard. The Universal Testing Machine was used to test the welded specimen. Microhardness Testing was also carried out on the base material and the Heat Affected Zone (HAZ) using Vickers Hardness Testing machine. The tensile tested specimens were used for metallurgical analysis using Scanning Electron Microscope (S.E.M.). Specimen prepared for metallurgical analysis were sectioned, mounted, ground and polished in accordance with recommended procedures in ASTM practice E 3-11. The metallurgical observations showed the existence of undulating topography of ductile fracture surfaces. The investigations reveals that the actual values of the Ultimate tensile strength of the weld were falling close with the predicted strength obtained through the proposed model. It can be concluded that the proposed model in this work can be utilised to predict tensile strength of the weld with more precision.
关键词： Design of Experiments,Ultimate tensile strength,316 L A.S.S,Response Surface Methodology (RSM),Nd:YAG Laser welding
更新于2025-09-23 15:19:57
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Thermal design for the package of high-power single-emitter laser diodes
摘要： An analytical three-dimensional thermal model is employed to perform the thermal design for the package of high-power single-emitter laser diodes. Thermal design curves for the heat sink and submount are presented in detail, for laser diodes subjected to several convective heat transfer conditions on the bottom of the heat sink. An effective heat spreading angle is proposed to characterize thermal design for the heat sink. A differential heat spreading angle is proposed to clearly manifest heat flow in the packages. Full width and length at 90% energy are introduced to reveal the requirement of submount width and length, respectively. The impact of coefficient of thermal expansion (CTE)-matched sandwiched submount on total heat dissipation is studied. Special discussion is presented for a commercial F-Mount laser diode, and it is found that current heat sink design leads to a 27.4% increase in thermal resistance relative to a free lateral diffusion package.
关键词： Thermal resistance,Heat spreading angle,Submount,Heat sink,Thermal design,High-power laser diodes
更新于2025-09-23 15:19:57
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Method for increasing the core count and area of high density optical fiber bundles
摘要： Current manufacturing methods limit the increase in both core count and the area for optical fiber bundles. Here a method for increasing the core count and hence the available image area of high density optical fiber bundles, through fusing multiple smaller sized sub-bundles is proposed and experimentally investigated. The key issue being investigated is whether it is possible to eliminate or reduce the dead-space between cylindrical sub-bundles, where no cores are present to spatially sample an image. Small sample lengths of fused optical fiber bundles are fabricated and characterized using an optical and scanning electron microscope to assess the reduction in dead-space and the optical losses near the interfaces. We demonstrate a 30% decrease in the dead-space area through fusing three equally sized sub-bundles in a triangular arrangement, while still retaining the light-guiding ability of more than 70% of the cores which transported into this region. We also assessed the optical losses for cores near the fused interfaces, at different wavelengths in the visible spectrum. A model of the propagation modes supported by the cores is explored which attributes these losses to the increasing eccentricity of cores near the fused interfaces.
关键词： optical fiber imaging,Multicore fiber,linearly polarized modes,fiber fabrication and design
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE International Symposium on Information Theory (ISIT) - Paris, France (2019.7.7-2019.7.12)] 2019 IEEE International Symposium on Information Theory (ISIT) - A Variational Signal-Space Distance Measure for Nondispersive Optical Fiber
摘要： The nondispersive per-sample channel model for the optical fiber channel is considered. Under some smoothness assumptions, the problem of finding the minimum amount of noise energy that can render two different input points indistinguishable is formulated. The necessary conditions for the noise trajectory that has the minimum energy are described as a system of nonlinear differential equations. It is suggested that this model can be generalized to consider dispersion and to design new communication schemes for fiber-optic communication systems.
关键词： variational approach,optical fiber,constellation design,adversarial model
更新于2025-09-23 15:19:57