Proposed enhancement of side-mode suppression ratio in λ/4 shifted distributed feedback lasers with nonuniform diffused quantum wells

An enhancement of the side mode suppression ratio, by utilizing interdiffused quantum wells, of a λ/4 shifted distributed feedback laser is demonstrated theoretically. It is found that by introducing a diffusion step along the longitudinal direction of the quantum-well active region, the suppression ratio can be improved significantly for large /spl kappa/L (>2.6) devices. The maximum power for single longitudinal mode operation is increased by more than 50 mW.published_or_final_versio

Enhancement of mode stability in vertical cavity surface emitting lasers with diffused quantum wells structure

The use of diffused quantum well structures to enhance single transverse mode operation in vertical cavity surface emitting GaAs-AlGaAs QW semiconductor lasers is proposed and analyzed theoretically.published_or_final_versio

Semiconductor lasers using diffused quantum-well structures

We assess the relative merits and prospects of using diffused quantum-well (QW) structures in semiconductor lasers. First, different techniques to achieve interdiffusion are analyzed and compared. Second, recent development of semiconductor lasers using interdiffusion technique is also discussed. Third, the optical properties of diffused QWs are studied. In addition, novel design of diffused QWs structures to maintain stable single-mode operation in semiconductor lasers is proposed. Finally, brief discussion and conclusion are given.published_or_final_versio

Identifying smart design attributes for Industry 4.0 customization using a clustering Genetic Algorithm

Industry 4.0 aims at achieving mass customization at a mass production cost. A key component to realizing this is accurate prediction of customer needs and wants, which is however a challenging issue due to the lack of smart analytics tools. This paper investigates this issue in depth and then develops a predictive analytic framework for integrating cloud computing, big data analysis, business informatics, communication technologies, and digital industrial production systems. Computational intelligence in the form of a cluster k-means approach is used to manage relevant big data for feeding potential customer needs and wants to smart designs for targeted productivity and customized mass production. The identification of patterns from big data is achieved with cluster k-means and with the selection of optimal attributes using genetic algorithms. A car customization case study shows how it may be applied and where to assign new clusters with growing knowledge of customer needs and wants. This approach offer a number of features suitable to smart design in realizing Industry 4.0

Influence of lateral field on the relaxation oscillation frequency of semiconductor lasers

We demonstrate theoretically that the lateral field distribution can be utilized to enhance the relaxation oscillation frequency of semiconductor lasers. It is found, for some laser parameters, that gain-guided semiconductor lasers with narrow stripe can exhibit higher relaxation oscillation frequency than index-guided devices.published_or_final_versio

Parallel approach to sliding window sums

Sliding window sums are widely used in bioinformatics applications, including sequence assembly, k-mer generation, hashing and compression. New vector algorithms which utilize the advanced vector extension (AVX) instructions available on modern processors, or the parallel compute units on GPUs and FPGAs, would provide a significant performance boost for the bioinformatics applications. We develop a generic vectorized sliding sum algorithm with speedup for window size w and number of processors P is O(P/w) for a generic sliding sum. For a sum with commutative operator the speedup is improved to O(P/log(w)). When applied to the genomic application of minimizer based k-mer table generation using AVX instructions, we obtain a speedup of over 5X.Comment: 10 pages, 5 figure

Formation of artificial granules for proving gelation as the main mechanism of aerobic granulation in biological wastewater treatment

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Time varying parameter and fixed parameter linear AIDS : an application to tourism demand forecasting

2005-2006 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Modeling tourism demand : a dynamic linear AIDS approach

2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Diffused-quantum-well vertical cavity Fabry-Perot reflectionmodulator

Conference theme: Asia-Pacific Microelectronics 2000This is a first report to use diffused quantum well (DFQW) as the active cavity of the Fabry-Perot reflection modulator. Apart from the simple fabrication process of the DFQW, this material system provides a wavelength tuning range and improves the modulation properties of the device which thus is competitive with the same kind of modulator.published_or_final_versio