scholarly journals Efficient Design for Integrated Photonic Waveguides with Agile Dispersion

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6651
Author(s):  
Zhaonian Wang ◽  
Jiangbing Du ◽  
Weihong Shen ◽  
Jiacheng Liu ◽  
Zuyuan He
Keyword(s):  
Integrated Circuit ◽  
Frequency Comb ◽  
Design Method ◽  
Chromatic Dispersion ◽  
Nonlinear Effects ◽  
Superior Performance ◽  
Efficient Design ◽  
Linear Dispersion ◽  
Dispersion Engineering ◽  
Low Dispersion

Chromatic dispersion engineering of photonic waveguide is of great importance for Photonic Integrated Circuit in broad applications, including on-chip CD compensation, supercontinuum generation, Kerr-comb generation, micro resonator and mode-locked laser. Linear propagation behavior and nonlinear effects of the light wave can be manipulated by engineering CD, in order to manipulate the temporal shape and frequency spectrum. Therefore, agile shapes of dispersion profiles, including typically wideband flat dispersion, are highly desired among various applications. In this study, we demonstrate a novel method for agile dispersion engineering of integrated photonic waveguide. Based on a horizontal double-slot structure, we obtained agile dispersion shapes, including broadband low dispersion, constant dispersion and slope-maintained linear dispersion. The proposed inverse design method is objectively-motivated and automation-supported. Dispersion in the range of 0–1.5 ps/(nm·km) for 861-nm bandwidth has been achieved, which shows superior performance for broadband low dispersion. Numerical simulation of the Kerr frequency comb was carried out utilizing the obtained dispersion shapes and a comb spectrum for 1068-nm bandwidth with a 20-dB power variation was generated. Significant potential for integrated photonic design automation can be expected.

scholarly journals Asymmetric Double Freeform Surface Lens for Integrated LED Automobile Headlamp

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 663
Author(s):  
Hui Zhang ◽  
Dengfei Liu ◽  
Yinwan Wei ◽  
Hong Wang
Keyword(s):  
Optical System ◽  
Design Method ◽  
Chromatic Dispersion ◽  
Electronic Devices ◽  
Color Temperature ◽  
Freeform Surface ◽  
United Nations Economic Commission ◽  
System A ◽  
Economic Commission ◽  
Key Points

We propose a design method of asymmetric double freeform surface lens for an integrated LED automobile headlamp and develop an integrated LED automobile optical system. A single asymmetric double freeform surface lens is designed to redistribute rays emitting from the light source for realizing both low and high beams. Moreover, a freeform surface reflector is used to improve the energy efficiency of high beams. The prism placed in the optical path can suppress chromatic dispersion on the edge of the target plane. Simulation and experimental results show that the illumination values and color temperature of the key points can fully meet the requirements of United Nations Economic Commission for Europe vehicle regulations (ECE) R112, 48, and 128. The volume of the whole optical system comprised of freeform surface elements is smaller than that of the low beam system of a traditional headlamp, resulting in saved space, in which other electronic devices can be installed for the safety of the driver, which indicates that the proposed method is practical in the field of automobile lighting.

An efficient design method for multi-material bolted joints used in the railway industry

2011 ◽  
Vol 94 (1) ◽  
pp. 246-252 ◽  
Author(s):  
G. Catalanotti ◽  
P.P. Camanho ◽  
P. Ghys ◽  
A.T. Marques
Keyword(s):  
Design Method ◽  
Bolted Joints ◽  
Efficient Design ◽  
Railway Industry

Aerodynamic Design and Optimization of Pipe Diffuser for a High-Loading Centrifugal Compressor

2017 ◽  
Author(s):  
Xi Yang ◽  
Dong-hai Jin ◽  
Xing-min Gui
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Simulation Software ◽  
Field Analysis ◽  
Superior Performance ◽  
Critical Cross Section ◽  
Isentropic Efficiency ◽  
Vane Diffuser

Pipe diffuser draws more attentions these years as the stage pressure ratio and loads grow, since it is known that the pipe diffuser has a superior performance to the traditional vane diffuser as the diffuser inlet flow field is transonic or supersonic. Generally speaking, when the pressure ratio is high enough to give rise to the emergence of a critical cross-section, it would usually be in the diffuser, closing to the leading edge other than in the impeller. Therefore, the diffuser would have a significant impact on stage choke margin and its performance while be difficult to design and to match the impeller with satisfaction. To address the problem, a preliminary geometry design method for pipe diffuser is presented in this paper. In this paper, the performance and flow field analysis are based on numerical simulation carried out by Numeca, a commercial simulation software. For verified the calculated results′ reliability and grid independence, corresponding calculations and comparisons are conducted and discussed. Then, the performance of stage with pipe diffuser is compared with the stage with vane diffuser. Next, the specific effects of incidence on the performance and flow field are analyzed and discussed respectively. At last, an optimized aerodynamic structure of pipe diffuser is presented. As shown in the CFD results, the stage peak isentropic efficiency can reach up to 83.65% with the stage total pressure ratio slightly increased from 6.50 to 6.78, which means 4.29% of isentropic efficiency was raised by substituting the pipe diffuser for the vane diffuser.

THz pulse train generation through ultrafast development of surface plasmon-polariton modulation instability

2021 ◽  
Author(s):  
Dmitry A Korobko ◽  
Igor O. Zolotovskii ◽  
Sergey Moiseev ◽  
Alexei S. Kadochkin ◽  
Vyacheslav Svetukhin
Keyword(s):  
Surface Plasmon ◽  
Electromagnetic Waves ◽  
Surface Plasmon Polariton ◽  
Modulation Instability ◽  
Frequency Comb ◽  
Nonlinear Effects ◽  
Wave Dispersion ◽  
Instability Effect ◽  
Plasmon Polariton ◽  
Plasmon Wave

Abstract Propagation of high-intensity electromagnetic waves in a waveguide structure could initiate nonlinear effects resulting in drastic changes of their spatial and temporal characteristics. We study the modulation instability effect induced by propagation of surface plasmon polaritons in a silver thin-film waveguide. The nonlinear Schrodinger equation for propagating surface plasmon wave is obtained. It is shown numerically that the modulation instability effect can give rise to ultrafast spatial redistribution and longitudinal localization of surface plasmon-polariton wave energy in subwavelength scale. The dependence of plasmon wave dispersion and nonlinear characteristics on metal film thickness is considered. We demonstrate that the use of films with the thickness varying along the waveguide length allows reduction of the generated pulse width and increase of frequency comb bandwidth. The proposed technique is promising for design of ultra-compact (tens of nm) optical generators delivering pulse trains with the repetition rate higher than 1THz.

scholarly journals Multi-Level Modeling Methodology for Optimal Design of Electric Machines Based on Multi-Disciplinary Design Optimization

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4173
Author(s):  
Zehua Dai ◽  
Li Wang ◽  
Lexuan Meng ◽  
Shanshui Yang ◽  
Ling Mao
Keyword(s):  
Power Systems ◽  
Design Optimization ◽  
Synchronous Generator ◽  
Electric Machines ◽  
Modeling Method ◽  
System Level ◽  
Superior Performance ◽  
Efficient Design ◽  
Modeling Methodology ◽  
Multi Level

The transportation sector is undergoing electrification to gain advantages such as lighter weight, improved reliability, and enhanced efficiency. As contributors to the safety of embedded critical functions in electrified systems, better sizing of electric machines in vehicles is required to reduce the cost, volume, and weight. Although the designs of machines are widely investigated, existing studies are mostly complicated and application-specific. To satisfy the multi-level design requirements of power systems, this study aims to develop an efficient modeling method of electric machines with a background of aircraft applications. A variable-speed variable-frequency (VSVF) electrically excited synchronous generator is selected as a case study to illustrate the modular multi-physics modeling process, in which weight and power loss are the major optimization goals. In addition, multi-disciplinary design optimization (MDO) methods are introduced to facilitate the optimal variable selection and simplified model establishment, which can be used for the system-level overall design. Several cases with industrial data are analyzed to demonstrate the effectiveness and superior performance of the modeling method. The results show that the proposed practices provide designers with accurate, fast, and systematic means to develop models for the efficient design of aircraft power systems.

scholarly journals A New Design Method for Ultrawideband Microstrip-to-Suspended Stripline Transitions

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Young-Gon Kim ◽  
Kang Wook Kim
Keyword(s):  
Conformal Mapping ◽  
Insertion Loss ◽  
Design Method ◽  
Impedance Matching ◽  
Characteristic Impedance ◽  
Ultra Wideband ◽  
Efficient Design ◽  
Em Simulation ◽  
Simulation Results ◽  
Analytical Expressions

A clear and efficient design method for ultra-wideband microstrip-to-suspended stripline transition, which is based on the analytical expressions of the whole transitional structure, is presented. The conformal mapping is applied to obtain the characteristic impedance of the transitional structure within 2.85% accuracy as compared with the EM-simulation results. The transition is designed to provide broadband impedance matching and smooth field conversion. The implemented transition performs less than 0.6 dB insertion loss per transition for frequencies up to 30 GHz.

GA-BASED DESIGN OF 2D STATE-SPACE DIGITAL FILTERS WITH LINEAR PHASE CHARACTERISTICS

2007 ◽  
Vol 16 (02) ◽  
pp. 287-303 ◽  
Author(s):  
SANG-CHURL NAM ◽  
MASAHIDE ABE ◽  
MASAYUKI KAWAMATA
Keyword(s):  
State Space ◽  
Design Problem ◽  
Digital Filters ◽  
Design Method ◽  
Design Procedure ◽  
Gray Code ◽  
Superior Performance ◽  
Magnitude Response ◽  
The Stability ◽  
Group Delays

This paper proposes a GA-based design method for two-dimensional (2D) state-space digital filters which satisfy simultaneously the magnitude response and constant group delays. The design problem of 2D state-space digital filters is formulated subject to the constraint that the resultant filters are stable. To apply the genetic algorithm to the design problem, all coefficients of 2D state-space digital filters are encoded into the Gray code representation demonstrating the superior performance to the standard binary one. In addition, a stability test routine is embedded in the design procedure in order to ensure the stability for the resultant filters. A numerical example is given to demonstrate the effectiveness of the proposed method.

scholarly journals Investigation of the Design and Fault Prediction Method for an Abrasive Particle Sensor Used in Wind Turbine Gearbox

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 365
Author(s):  
Le Zhang ◽  
Qiang Yang
Keyword(s):  
Wind Turbine ◽  
Design Method ◽  
Abrasive Particle ◽  
Prediction Method ◽  
Fault Prediction ◽  
Superior Performance ◽  
Lubricating Oil ◽  
Operation Performance ◽  
Wind Turbine Gearbox ◽  
Abrasive Particles

The gearbox is a key sub-component of a wind power generation system with high failure rate leading to shutdowns. By monitoring the abrasive particles in the lubricating oil when the gearbox is running, any abnormal condition of the gearbox can be found in advance. This information may be used to improve the operational safety of the wind turbine and reduce losses because of shutdowns and maintenance. In this paper, a three-coil induction abrasive particle sensor is designed based on the application of high-power wind turbine gearbox. The performance of the sensor and the design method of the detection circuit are described in detail, and the sensor operation performance used in the 2 MW wind turbine is verified. The results show that the sensor has superior performance in identifying ferromagnetic abrasive particles above 200 μm and plays a good role in status monitoring and fault prediction for the gearbox.

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