Hybrid Si/III-V, Fabry-Perot evanescent lasers are demonstrated, utilizing InGaAsP as the III-V gain material for first time to our knowledge. The lasing threshold current of 300-mum-long devices was low 24 mA, with a maximal single facet output power 4.2 mW at 15 degrees C. Longer achieved high 12.7 mW, slope efficiency 8.4%, and density 1 kA/cm2. Continuous wave laser operation obtained up 45 density, power, improve upon those previously reported having similar geometry. Facet images...

This paper presents a two-dimensional (2-D) analytical model for plannar linear permanent-magnet (PM) synchronous motors. The general and particular solutions are presented slotless single-sided PM motor as case study. governing partial differential equations of the formulated seven regions: mover side exterior, back iron, PMs, air-gap, winding, stator back-iron, stator-side exterior. Four different magnetization patterns, i.e., parallel, ideal Halbach, 2-segment bar magnets in shifting...

Single quantum well, graded refractive index separate confinement heterostucture (SQW GRINSCH) lasers with well thicknesses in the range of 65–480 Å have been grown by molecular beam epitaxy (MBE) on (100) and off 4° toward (111) A substrates. The threshold current density appears to be independent thickness 65–165 due compensating effects volume inversion optical confinement. Under optimum growth conditions, tilted substrates led lower densities, lowest value being 93 A/cm2 for a...

Consequent-pole permanent-magnet machines are of particular interest owing to their special features. They have alternate hard and soft magnet poles. In this paper, a two-dimensional (2-D) analytical model is proposed for outer-rotor slotted-stator consequent-pole brushless PM (CPBLPM) machines. The developed from the quasi-magneto-static Maxwell's equations, which analytically solved. magnetic flux density expressions initially derived then other quantities such as no-load induced voltage,...

Room-temperature continuous-wave operation of large-area (120 μm × 980 μm) GaAs/AlGaAs graded-refractive-index separate-confinement heterostructure lasers on (100) Si substrates has been obtained. Minimum threshold-current densities 214 A/cm2 (1900-μm cavity length), maximum slope efficiencies about 0.8 W/A (600-μm length),and optical power in excess 270 mW/facet (900-μm length) have observed under pulsed conditions.

Low-threshold graded-refractive-index GaAs/AlGaAs laser structures were grown on Si (100) by molecular beam epitaxy and tested at room temperature under a probe station. Broad area devices having widths of 110–120 μm cavity lengths ∼500–1210 exhibited threshold current densities as low 600 A/cm2 total slope efficiencies high 0.75 W/A. The thresholds fell in the range 600–1000 three different wafers, it is assumed that quality facets accounts for most spread results.

The formation, expansion, and readjustment of electric field domains in multiquantum well stacks is described explained terms sequential resonant tunneling. These effects are used to control the multiband spectral response IR detector applications these structures.

Threshold current densities as low 80 A/cm2 for 3.3 mm-long cavity lasers, and 93 520 μm-long lasers have been obtained in AlGaAs/GaAs graded-index separate-confinement heterostructure (GRINSCH) single-quantum-well with quantum-well widths between 65–165 A grown by molecular beam epitaxy. The structures were prepared on (100) GaAs substrates do not display the earlier reported dependence of lasing threshold characteristics thickness range studied (65–165 A).

This paper presents a two-dimensional analytical model of outer rotor permanent magnet machines equipped with surface inset magnets. To obtain the model, whole is divided into sub-domains, according to magnetic properties and geometries. Maxwell equations in each sub-domain are expressed analytically solved. By using boundary/interface conditions between adjacent sub-regions, integral coefficients general solutions obtained. At end, calculated results air-gap flux density, electromagnetic...

This paper estimates the magnetic flux density components in slotless single-sided axial permanent-magnet synchronous machines (SAFPMSMs). For this purpose, a 2-D analytical model based on sub-domain method is utilized which cross-section of presented machine divided into seven sub-regions such as stator side exterior, stator, winding, air-gap, permanent-magnets (PMs), mover and exterior. Based Maxwell equations, related partial differential equations (PDEs) are formed each sub-region...

Abstract The objective of this paper is to investigate the optimal design a 120 W outer‐rotor permanent magnet synchronous machine for air‐conditioning applications reduce electricity consumption and costs. To end, 2‐D analytical magnetic model, combined with teaching–learning based optimisation algorithm employed. objectives are simultaneously maximise efficiency minimise material cost. Constraints such as required output torque, predefined volume, maximum allowable torque ripple unbalanced...

Slotless double-sided outer armature permanent-magnet (PM) linear motors (SDOPMLs) have high efficiency and low detent force.Despite their simple control strategy easy manufacturing process, finding an accurate model of these to calculate the machine quantities is challenging.It particularly critical for obtaining optimum design machines which may include too many iterations in a short time.To overcome this challenge, 2-D analytical based on subdomain method presented determine magnetic flux...

This article compares the 2-D and 0-D analytical models for slotless double-sided inner armature linear permanent magnet synchronous machines (SDSIALPMSMs). The sub-domain method is implemented to achieve model. In this method, cross-section of motor divided into eleven sub-regions Maxwell equations are determined each sub-region. presented model, a magnetic equivalent circuit (MEC) derived compute maximum flux density in air-gap. both approaches, analytically calculated predict inductance,...

To enhance the mechanical and compressive strength of lime mortar(lime-sand ) fly ash was added to compound improved engineering performance mixture .The addition stone dust clay soils reduce their plasticity characteristics, swell potential improve (Brooks et al. 2011) .Boardman al (2001) observed that no significant pozzolonic activity appears take place until 7 days curing during experiments at room temperature .In this research effect different range from 30 70 percent mix by varying...

A new hetero-Schottky structure for the study of Schottky barriers and heterojunctions is discussed. Photoelectric measurements have revealed a correlation between Au/GaAs Au/AlxGa1−xAs barrier heights GaAs/AlxGa1−xAs heterojunction band offsets. The conduction-band discontinuity ΔEc in system determined, ratio ΔEc:ΔEg found to vary 69±5% 58±5% x=0.15–0.48.

Microwave modulation and CW operation of AlGaAs lasers grown by MBE on Si substrates have been obtained for the first time. Ridge waveguide lasers(10µm×380µm) were modulated with a microwave signal up to 2.5GHz which is notable considering structure used. Near far field measurements indicated single transverse mode narrow beam angle (4.8°). Finally, polarization appear show solely TE nature emission.

Analytical approaches, if possible, are suggested for saving the simulation time in design stage of electrical machines. This benefit is highlighted when optimization issues including too many iterations desired. Hence, this paper presents a 2-D analytical model magnetic field distribution based on sub-domain method slotless double-sided axial flux permanent-magnet (PM) brushless machines (AFPMBMs) with internal-rotor-external-stators. According to method, machine cross-section divided into...

This paper presents a 2D analytical model for predicting the magnetic flux density distribution in slotless permanent-magnet (PM) linear tubular (PMLT) motors due to armature reaction effects based on sub-domain method. According this method, machine cross-section is divided into six sub-regions and Maxwell partial differential equations (PDEs) are formed each sub-region. Solving these PDEs leads defining vector potential sub-region applying curl calculated results determining components....

An experimental research of the bonds amongst retrofitted materials on concrete structures under seashore climate has conducted. The strength a bond between repair and substratum been assessed base slant shear test experiment. In this 52 samples prepared used for experiment .The fresh with fine aggregate mix only (less than 9mm particle size without coarse aggregate) 14% silica fume by weight cement (normally 8 to 10% but because high amount ) added which improve properties such as well...

Hybrid Si/InGaAsP Fabry-Perot evanescent lasers are fabricated via wafer bonding. Compared with previous similar devices, the current threshold density, turn-on voltage, output power and slope efficiency all improved. Images show modal confinement to Silicon.

Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text H. Z. CHEN, A. GHAFFARI, WANG, MORKOÇ, and YARIV, "Continuous wave operation of Ga/As lasers Si substrates," Optics News 13(12), 12_1-13 (1987) Export BibTex Endnote (RIS) HTML Plain alert Save article

Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text H. Z. CHEN, A. GHAFFARI, WANG, MORKOÇ, and YARIV, "Continuous wave operation of Ga/As lasers Si substrates," Optics News 13(12), 12_1-13 (1987) Export BibTex Endnote (RIS) HTML Plain alert Save article