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Pumping Scheme (pumping + scheme)

Distribution by Scientific Domains
Engineering75%

Selected Abstracts

Investigation on the effect of stimulated Raman scattering in remotely-pumped L-band erbium-doped fiber amplifier

LASER PHYSICS LETTERS, Issue 8 2009
M.H. Abu Bakar
Abstract The effect of stimulated Raman scattering (SRS) in remote pumping scheme for L-band erbium-doped fiber amplifier (EDFA) was studied in this experiment. Observation was done on the gain and noise figure performance as well as the Raman distributed gains of the remotely-pumped L-band erbium-doped fiber amplifier with the existence of SRS. The utilization of SRS effect as a secondary pump for L-band EDFA demonstrated improvements over single pump EDFA at low pump power due to the additional power from the generated C-band stimulated Raman scattering or SRS. Nevertheless, the augmentation of the Cband SRS power as the pump was increased, caused gain competition with the L-band signal which ultimately affected the performance of the L-band EDFA. The Raman distributed gain was also influenced by the C-band SRS existence, which saw declining L-band gains as the C-band SRS rose and then improved values once the C-band SRS is saturated. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Single-mode pumping scheme for EDFA with high-power conversion efficiency using a 980-NM Ti:S laser

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2006
M. A. Mahdi
Abstract In this paper, we demonstrate a high-power erbium-doped fiber amplifier pumped by single-mode titanium sapphire (Ti:S) laser at 980 nm. The highest output power of 22.6 dBm is measured at 1549 nm with an input signal power of 4 dBm and a pump power of 300 mW. This corresponds to power-conversion efficiency (PCE) of 60%, providing 95% quantum efficiency. The experimental results show the feasibility of using a single-mode laser from a high-power semiconductor chip to produce high-efficiency booster amplifiers. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 71,74, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21264 [source]

Ground Water Sustainability: Methodology and Application to the North China Plain

GROUND WATER, Issue 6 2008
Jie Liu
This article analyzes part of a ground water flow system in the North China Plain (NCP) subject to severe overexploitation and rapid depletion. A transient ground water flow model was constructed and calibrated to quantify the changes in the flow system since the predevelopment 1950s. The flow model was then used in conjunction with an optimization code to determine optimal pumping schemes that improve ground water management practices. Finally, two management scenarios, namely, urbanization and the South-to-North Water Transfer Project, were evaluated for their potential impacts on the ground water resources in the study area. Although this study focuses on the NCP, it illustrates a general modeling framework for analyzing the sustainability, or the lack thereof, of ground water flow systems driven by similar hydrogeologic and economic conditions. The numerical simulation is capable of quantifying the various components of the overall flow budget and evaluating the impacts of different management scenarios. The optimization modeling allows the determination of the maximum "sustainable pumping" that satisfies a series of prescribed constraints. It can also be used to minimize the economic costs associated with ground water development and management. Furthermore, since the NCP is one of the most water scarce and economically active regions in the world, the conclusions and insights from this study are of general interest and international significance. [source]

Modeling of a Deep-Seated Geothermal System Near Tianjin, China

GROUND WATER, Issue 3 2001
Zhou Xun
A geothermal field is located in deep-seated basement aquifers in the northeastern part of the North China Plain near Tianjin, China. Carbonate rocks of Ordovician and Middle and Upper Proterozoic age on the Cangxian Uplift are capable of yielding 960 to 4200 m3/d of 57°C to 96°C water to wells from a depth of more than 1000 m. A three-dimensional nonisothermal numerical model was used to simulate and predict the spatial and temporal evolution of pressure and temperature in the geothermal system. The density of the geothermal water, which appears in the governing equations, can be expressed as a linear function of pressure, temperature, and total dissolved solids. A term describing the exchange of heat between water and rock is incorporated in the governing heat transport equation. Conductive heat flow from surrounding formations can be considered among the boundary conditions. Recent data of geothermal water production from the system were used for a first calibration of the numerical model. The calibrated model was used to predict the future changes in pressure and temperature of the geothermal water caused by two pumping schemes. The modeling results indicate that both pressure and temperature have a tendency to decrease with time and pumping. The current withdrawal rates and a pumping period of five months followed by a shut-off period of seven months are helpful in minimizing the degradation of the geothermal resource potential in the area. [source]