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Publisher: Hindawi   (Total: 334 journals)

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Showing 1 - 200 of 334 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.512, h-index: 32)
Active and Passive Electronic Components     Open Access   (Followers: 7, SJR: 0.157, h-index: 15)
Advances in Acoustics and Vibration     Open Access   (Followers: 24, SJR: 0.259, h-index: 6)
Advances in Agriculture     Open Access   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 14)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Astronomy     Open Access   (Followers: 34, SJR: 0.351, h-index: 17)
Advances in Bioinformatics     Open Access   (Followers: 18, SJR: 0.421, h-index: 8)
Advances in Biology     Open Access   (Followers: 8)
Advances in Chemistry     Open Access   (Followers: 12)
Advances in Civil Engineering     Open Access   (Followers: 33, SJR: 0.338, h-index: 8)
Advances in Condensed Matter Physics     Open Access   (Followers: 8, SJR: 0.248, h-index: 10)
Advances in Decision Sciences     Open Access   (Followers: 4, SJR: 0.231, h-index: 6)
Advances in Ecology     Open Access   (Followers: 13)
Advances in Electrical Engineering     Open Access   (Followers: 18)
Advances in Endocrinology     Open Access   (Followers: 1)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.258, h-index: 7)
Advances in Hematology     Open Access   (Followers: 9, SJR: 0.892, h-index: 18)
Advances in High Energy Physics     Open Access   (Followers: 21, SJR: 0.892, h-index: 19)
Advances in Human-Computer Interaction     Open Access   (Followers: 19, SJR: 0.439, h-index: 9)
Advances in Materials Science and Engineering     Open Access   (Followers: 30, SJR: 0.263, h-index: 11)
Advances in Mathematical Physics     Open Access   (Followers: 6, SJR: 0.332, h-index: 10)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Meteorology     Open Access   (Followers: 18, SJR: 0.498, h-index: 10)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.191, h-index: 10)
Advances in Neuroscience     Open Access   (Followers: 8)
Advances in Nonlinear Optics     Open Access   (Followers: 5)
Advances in Numerical Analysis     Open Access   (Followers: 3)
Advances in Nursing     Open Access   (Followers: 21)
Advances in Operations Research     Open Access   (Followers: 11, SJR: 0.343, h-index: 7)
Advances in Optical Technologies     Open Access   (Followers: 3, SJR: 0.283, h-index: 16)
Advances in OptoElectronics     Open Access   (Followers: 5, SJR: 0.973, h-index: 16)
Advances in Orthopedic Surgery     Open Access   (Followers: 9)
Advances in Orthopedics     Open Access   (Followers: 9)
Advances in Pharmacological Sciences     Open Access   (Followers: 5, SJR: 0.695, h-index: 13)
Advances in Physical Chemistry     Open Access   (Followers: 11, SJR: 0.297, h-index: 7)
Advances in Power Electronics     Open Access   (Followers: 20, SJR: 0.26, h-index: 6)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 19)
Advances in Software Engineering     Open Access   (Followers: 10)
Advances in Tribology     Open Access   (Followers: 10, SJR: 0.267, h-index: 6)
Advances in Urology     Open Access   (Followers: 10, SJR: 0.629, h-index: 16)
Advances in Virology     Open Access   (Followers: 7, SJR: 1.04, h-index: 12)
AIDS Research and Treatment     Open Access   (Followers: 3, SJR: 1.125, h-index: 14)
Analytical Cellular Pathology     Open Access   (Followers: 1, SJR: 0.334, h-index: 12)
Anatomy Research Intl.     Open Access   (Followers: 1)
Anemia     Open Access   (Followers: 4, SJR: 0.991, h-index: 11)
Anesthesiology Research and Practice     Open Access   (Followers: 13, SJR: 0.513, h-index: 12)
Applied and Environmental Soil Science     Open Access   (Followers: 15, SJR: 0.53, h-index: 9)
Applied Bionics and Biomechanics     Open Access   (Followers: 8, SJR: 0.23, h-index: 13)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Archaea     Open Access   (Followers: 3, SJR: 1.248, h-index: 27)
Arthritis     Open Access   (Followers: 4)
Autism Research and Treatment     Open Access   (Followers: 29)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.909, h-index: 17)
Behavioural Neurology     Open Access   (Followers: 7, SJR: 0.696, h-index: 34)
Biochemistry Research Intl.     Open Access   (Followers: 6, SJR: 1.085, h-index: 17)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9, SJR: 0.286, h-index: 19)
BioMed Research Intl.     Open Access   (Followers: 6, SJR: 0.725, h-index: 59)
Biotechnology Research Intl.     Open Access   (Followers: 2)
Bone Marrow Research     Open Access   (Followers: 2)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 3, SJR: 0.856, h-index: 53)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 3, SJR: 0.409, h-index: 25)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.503, h-index: 42)
Cardiology Research and Practice     Open Access   (Followers: 7, SJR: 0.941, h-index: 17)
Cardiovascular Psychiatry and Neurology     Open Access   (Followers: 4, SJR: 1.091, h-index: 14)
Case Reports in Anesthesiology     Open Access   (Followers: 10)
Case Reports in Cardiology     Open Access   (Followers: 2)
Case Reports in Critical Care     Open Access   (Followers: 8)
Case Reports in Dentistry     Open Access   (Followers: 3)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 13)
Case Reports in Endocrinology     Open Access   (SJR: 0.326, h-index: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 3)
Case Reports in Genetics     Open Access   (Followers: 1)
Case Reports in Hematology     Open Access   (Followers: 2)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 4)
Case Reports in Infectious Diseases     Open Access   (Followers: 5)
Case Reports in Medicine     Open Access   (Followers: 3)
Case Reports in Nephrology     Open Access   (Followers: 4)
Case Reports in Neurological Medicine     Open Access   (Followers: 1)
Case Reports in Obstetrics and Gynecology     Open Access   (Followers: 10)
Case Reports in Oncological Medicine     Open Access   (Followers: 2)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 2)
Case Reports in Orthopedics     Open Access   (Followers: 7)
Case Reports in Otolaryngology     Open Access   (Followers: 5)
Case Reports in Pathology     Open Access   (Followers: 3)
Case Reports in Pediatrics     Open Access   (Followers: 5)
Case Reports in Psychiatry     Open Access   (Followers: 10)
Case Reports in Pulmonology     Open Access   (Followers: 2)
Case Reports in Radiology     Open Access   (Followers: 8)
Case Reports in Rheumatology     Open Access   (Followers: 4)
Case Reports in Surgery     Open Access   (Followers: 7)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 8)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Chemotherapy Research and Practice     Open Access   (Followers: 1)
Child Development Research     Open Access   (Followers: 13)
Chinese J. of Engineering     Open Access   (Followers: 2)
Chinese J. of Mathematics     Open Access  
Cholesterol     Open Access   (Followers: 1, SJR: 0.906, h-index: 12)
Chromatography Research Intl.     Open Access   (Followers: 7)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.415, h-index: 22)
Computational Intelligence and Neuroscience     Open Access   (Followers: 9, SJR: 0.232, h-index: 30)
Critical Care Research and Practice     Open Access   (Followers: 9, SJR: 0.916, h-index: 14)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.8, h-index: 12)
Dataset Papers in Science     Open Access  
Depression Research and Treatment     Open Access   (Followers: 13, SJR: 0.77, h-index: 11)
Dermatology Research and Practice     Open Access   (Followers: 2, SJR: 0.576, h-index: 15)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.651, h-index: 18)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.323, h-index: 24)
Disease Markers     Open Access   (Followers: 1, SJR: 0.774, h-index: 49)
Economics Research Intl.     Open Access   (Followers: 2)
Education Research Intl.     Open Access   (Followers: 18)
Emergency Medicine Intl.     Open Access   (Followers: 6)
Enzyme Research     Open Access   (Followers: 4, SJR: 0.457, h-index: 18)
Epidemiology Research Intl.     Open Access   (Followers: 10)
Epilepsy Research and Treatment     Open Access   (Followers: 3)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 18, SJR: 0.615, h-index: 50)
Experimental Diabetes Research     Open Access   (Followers: 10, SJR: 1.591, h-index: 30)
Gastroenterology Research and Practice     Open Access   (Followers: 3, SJR: 0.664, h-index: 21)
Genetics Research Intl.     Open Access   (Followers: 1)
Hepatitis Research and Treatment     Open Access   (Followers: 6)
HPB Surgery     Open Access   (Followers: 5, SJR: 0.798, h-index: 22)
Indian J. of Materials Science     Open Access  
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 7, SJR: 0.976, h-index: 34)
Influenza Research and Treatment     Open Access   (Followers: 2)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 2, SJR: 0.763, h-index: 15)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 65, SJR: 0.241, h-index: 6)
Intl. J. of Agronomy     Open Access   (Followers: 8, SJR: 0.223, h-index: 2)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 11, SJR: 1.193, h-index: 25)
Intl. J. of Analysis     Open Access  
Intl. J. of Analytical Chemistry     Open Access   (Followers: 21, SJR: 0.157, h-index: 2)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 9, SJR: 0.385, h-index: 15)
Intl. J. of Atmospheric Sciences     Open Access   (Followers: 23)
Intl. J. of Bacteriology     Open Access  
Intl. J. of Biodiversity     Open Access   (Followers: 4)
Intl. J. of Biomaterials     Open Access   (Followers: 5, SJR: 0.485, h-index: 10)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 5, SJR: 0.581, h-index: 23)
Intl. J. of Breast Cancer     Open Access   (Followers: 12)
Intl. J. of Carbohydrate Chemistry     Open Access   (Followers: 7)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 2.658, h-index: 25)
Intl. J. of Chemical Engineering     Open Access   (Followers: 7, SJR: 0.361, h-index: 10)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Combinatorics     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 11, SJR: 0.213, h-index: 12)
Intl. J. of Corrosion     Open Access   (Followers: 10, SJR: 0.19, h-index: 7)
Intl. J. of Dentistry     Open Access   (Followers: 6, SJR: 0.558, h-index: 11)
Intl. J. of Differential Equations     Open Access   (Followers: 6, SJR: 0.363, h-index: 11)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.144, h-index: 10)
Intl. J. of Ecology     Open Access   (Followers: 7, SJR: 0.8, h-index: 11)
Intl. J. of Electrochemistry     Open Access   (Followers: 6)
Intl. J. of Endocrinology     Open Access   (Followers: 3, SJR: 0.961, h-index: 24)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 3)
Intl. J. of Evolutionary Biology     Open Access   (Followers: 9)
Intl. J. of Family Medicine     Open Access   (Followers: 2)
Intl. J. of Food Science     Open Access   (Followers: 3)
Intl. J. of Forestry Research     Open Access   (Followers: 4)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.721, h-index: 7)
Intl. J. of Geophysics     Open Access   (Followers: 5, SJR: 0.416, h-index: 8)
Intl. J. of Hepatology     Open Access   (Followers: 3)
Intl. J. of Hypertension     Open Access   (Followers: 5, SJR: 0.823, h-index: 20)
Intl. J. of Inflammation     Open Access   (SJR: 0.876, h-index: 14)
Intl. J. of Inorganic Chemistry     Open Access   (Followers: 2)
Intl. J. of Manufacturing Engineering     Open Access   (Followers: 2)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.346, h-index: 27)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6)
Intl. J. of Metals     Open Access   (Followers: 4)
Intl. J. of Microbiology     Open Access   (Followers: 5, SJR: 1.006, h-index: 18)
Intl. J. of Microwave Science and Technology     Open Access   (Followers: 4, SJR: 0.167, h-index: 5)
Intl. J. of Molecular Imaging     Open Access  
Intl. J. of Navigation and Observation     Open Access   (Followers: 19, SJR: 0.411, h-index: 7)
Intl. J. of Nephrology     Open Access   (Followers: 2, SJR: 0.926, h-index: 14)
Intl. J. of Oceanography     Open Access   (Followers: 8)
Intl. J. of Optics     Open Access   (Followers: 6, SJR: 0.262, h-index: 7)
Intl. J. of Otolaryngology     Open Access   (Followers: 1)
Intl. J. of Pediatrics     Open Access   (Followers: 4)
Intl. J. of Peptides     Open Access   (Followers: 4, SJR: 0.73, h-index: 16)
Intl. J. of Photoenergy     Open Access   (Followers: 2, SJR: 0.348, h-index: 28)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 1.578, h-index: 20)
Intl. J. of Polymer Science     Open Access   (Followers: 23, SJR: 0.265, h-index: 11)
Intl. J. of Population Research     Open Access   (Followers: 2)
Intl. J. of Proteomics     Open Access   (Followers: 1)
Intl. J. of Quality, Statistics, and Reliability     Open Access   (Followers: 13, SJR: 0.345, h-index: 4)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.182, h-index: 8)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 5)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 1.015, h-index: 18)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.402, h-index: 19)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 4, SJR: 0.234, h-index: 19)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.753, h-index: 11)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 3, SJR: 0.757, h-index: 14)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.865, h-index: 16)
Intl. J. of Vehicular Technology     Open Access   (Followers: 4, SJR: 0.169, h-index: 6)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.389, h-index: 8)
Intl. Scholarly Research Notices     Open Access   (Followers: 199)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 10)

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Journal Cover Advances in OptoElectronics
  [SJR: 0.973]   [H-I: 16]   [5 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1687-563X - ISSN (Online) 1687-5648
   Published by Hindawi Homepage  [334 journals]
  • Propagation in Diagonal Anisotropic Chirowaveguides

    • Abstract: A theoretical study of electromagnetic wave propagation in parallel plate chirowaveguide is presented. The waveguide is filled with a chiral material having diagonal anisotropic constitutive parameters. The propagation characterization in this medium is based on algebraic formulation of Maxwell’s equations combined with the constitutive relations. Three propagation regions are identified: the fast-fast-wave region, the fast-slow-wave region, and the slow-slow-wave region. This paper focuses completely on the propagation in the first region, where the dispersion modal equations are obtained and solved. The cut-off frequencies calculation leads to three cases of the plane wave propagation in anisotropic chiral medium. The particularity of these results is the possibility of controlling the appropriate cut-off frequencies by choosing the adequate physical parameters values. The specificity of this study lies in the bifurcation modes confirmation and the possible contribution to the design of optical devices such as high-pass filters, as well as positive and negative propagation constants. This negative constant is an important feature of metamaterials which shows the phenomena of backward waves. Original results of the biaxial anisotropic chiral metamaterial are obtained and discussed.
      PubDate: Wed, 08 Mar 2017 09:20:12 +000
       
  • Temperature Dependence Study of Mesa-Type InGaAs/InAlAs Avalanche
           Photodiode Characteristics

    • Abstract: Avalanche photodiodes (APDs) are key optical receivers due to their performance advantages of high speed, high sensitivity, and low noise. The most critical device parameters of APD include the avalanche breakdown voltage and dark current. In this work, we study the temperature dependence of the breakdown voltage and dark current of the mesa-type APD over a wide temperature range of 20–145°C. We institute an empirical model based on impact ionization processes to account for the experimental data. It is shown that highly stable breakdown characteristics of mesa-type APD can be attained with the optimization of the multiplication layer design. We have achieved excellent stability of avalanche breakdown voltage with a temperature coefficient of 0.017 V/°C. The temperature dependence of dark current is attributed to generation-recombination mechanism. The bandgap energy is estimated to be about 0.71 eV based on the temperature variation of dark current, in good agreement with the value for InGaAs.
      PubDate: Thu, 12 Jan 2017 00:00:00 +000
       
  • Coupling Characteristics of Fused Optical Fiber Coupler Formed with
           Single-Mode Fiber and Photonic Crystal Fiber Having Air Hole Collapsed
           Taper

    • Abstract: Fused coupler forming with a single-mode fiber (SMF) and a photonic crystal fiber (PCF) is one of the solutions for optical coupling from a light source to a PCF. In this paper, we presented coupling characteristics of a fused fiber coupler formed with an ordinary SMF and a PCF having air hole collapsed taper. A prototype of SMF-PCF coupler with air hole collapsed taper was fabricated using CO2 laser irradiation. The coupling efficiency from SMF to PCF was −6.2 dB at 1554 nm wavelength in the fabricated coupler. The structure of the SMF-PCF coupler to obtain high coupling efficiency was theoretically clarified by beam propagation analysis using an equivalent model of the coupler with simplification. It was clarified that appropriately choosing the prestretched or etched SMF diameter and the length of air hole collapsed region was effective to obtain high coupling efficiency that was a result of high extinction ratio at cross port and low excess loss. We also demonstrated that the diameter of prestretched SMF to obtain high coupling efficiency was insensitive to the air hole diameter ratio to pitch of the PCF in the air hole collapsed SMF-PCF coupler.
      PubDate: Thu, 24 Nov 2016 14:31:23 +000
       
  • An Iterative Method for the Uniformity Improvement of Edge-Lit Backlight

    • Abstract: A simple iterative optimization method is developed to improve the exiting light uniformity of the edge-lit backlight module. The method uses the relative deviation of the average luminous flux of the entire light guide plate (LGP) and the luminous flux of each region as constraint criterion and the ratio of the luminous flux of each region to the average luminous flux of the LGP as adjustment coefficient to adjust the density of the microstructures in each region. This process loops until the relative deviations of all regions meet a prespecified threshold value. A LGP based on microprism structure is presented to validate the method. The initial values, which represent the size of the microstructures manufactured on the bottom surfaces of the LGP, -dependent luminous fluxes, microstructure size distributions, iterations of the LGP, and the relative deviation of each region are discussed. The simulation results show that it is a very practical method for the uniformity improvement of the backlight when an appropriate initial value is selected and the final uniformity is better than 90% after optimization.
      PubDate: Wed, 28 Sep 2016 14:08:21 +000
       
  • Characteristics of Highly Birefringent Photonic Crystal Fiber with
           Defected Core and Equilateral Pentagon Architecture

    • Abstract: A novel high birefringence and nearly zero dispersion-flattened photonic crystal fiber (PCF) with elliptical defected core (E-DC) and equilateral pentagonal architecture is designed. By applying the full-vector finite element method (FEM), the characteristics of electric field distribution, birefringence, and chromatic dispersion of the proposed E-DC PCF are numerically investigated in detail. The simulation results reveal that the proposed PCF can realize high birefringence, ranging from 1 to 1 orders of magnitude, owing to the embedded elliptical air hole in the core center. However, the existence of the elliptical air hole gives rise to an extraordinary electric field distribution, where a V-shaped notch appears and the size of the V-shaped notch varies at different operating wavelengths. Also, the mode field diameter is estimated to be about 2 μm, which implies the small effective mode area and highly nonlinear coefficient. Furthermore, the investigation of the chromatic dispersion characteristic shows that the introduction of the elliptical air hole is helpful to control the chromatic dispersion to be negative or nearly zero flattened over a wide wavelength bandwidth.
      PubDate: Mon, 29 Aug 2016 14:12:15 +000
       
  • Polarization Sensitive Reflection and Dielectric Spectra in GaSe Thin
           Films

    • Abstract: The light polarization effects on the optical reflective and dielectric spectra of GaSe thin films are studied in the incident light wavelength range of 200–1100 nm. In this range of measurement, the angle of incidence () of light was varied between 30° and 80°. In addition, at of 30° the light polarizing angle () was altered in the range of 0–90°. Regardless of the value of , for all , the total reflectance sharply decreased with increasing . In addition, when is fixed at 30° and was varied, the amplitudes ratio of the polarized waves exhibits a resonance-antiresonance phenomenon at a wavelength that coincides with the film’s thickness (800 nm). This behavior was assigned to the coupled interference between incident and reflected waves and to the strong absorption effects. Two main resonance peaks are observed as response to -polarized and normal incident beam: one is at ~540 (556 nm) and the other at ~420 THz (714 nm). The dielectric constant of the GaSe films exhibits anisotropic characteristics that nominate it for use as multipurpose optoelectronic devices.
      PubDate: Sun, 31 Jul 2016 10:10:40 +000
       
  • Study of a Linear Acoustooptic Laser Modulator Based on All-Fibre Sagnac
           Interferometer

    • Abstract: The feasibility of polarization-maintaining photonic crystal fibre (PM-PCF) strategy for acoustooptic modulation using all-fibre Sagnac interferometer is demonstrated. The principal constraint to apply the strategy is defined by a linear laser acoustooptic modulator (AOM) for 1550 nm. The intensity of incident acoustic waves over the PM-PCF loop segment affected the signal interference transmission; here, modulation by birefringence variation around was observed. It is discovered that, through mathematical analysis, two operation points in the spectrum, , operate in a linear region, and expressions for spectral gain and sensibility are also discovered. AOM has a bandwidth from 0.1 Hz to 20 kHz, and its dynamic range is from 0.0 to 43.5 dB.
      PubDate: Mon, 25 Jul 2016 07:51:56 +000
       
  • Noise Gain Features of Fiber Raman Amplifier

    • Abstract: The formation dynamics of the optical noise in a silica single mode fiber (SMF) as function of the pump power variation in the counter pumped fiber Raman amplifier (FRA) is experimentally studied. The ratio between the power of amplified spontaneous emission and the power of incoherent optical noise is quantitatively determined by detailed analysis of experimental data in the pump powers range of 100–300 mW within the full band of Stokes frequencies, including FRA working wavelengths over the C + L transparency windows. It is found out the maximum of Raman gain coefficient for optical noise does not exceed ~60% of corresponding peak at the gain profile maximum of coherent signal. It is shown that the real FRA noise figure may be considerably less than 3 dB over a wide wavelength range (100 nm) at a pump power of several hundreds of mW.
      PubDate: Tue, 12 Jul 2016 14:30:36 +000
       
  • A Grooming Nodes Optimal Allocation Method for Multicast in WDM Networks

    • Abstract: The grooming node has the capability of grooming multicast traffic with the small granularity into established light at high cost of complexity and node architecture. In the paper, a grooming nodes optimal allocation (GNOA) method is proposed to optimize the allocation of the grooming nodes constraint by the blocking probability for multicast traffic in sparse WDM networks. In the proposed GNOA method, the location of each grooming node is determined by the SCLD strategy. The improved smallest cost largest degree (SCLD) strategy is designed to select the nongrooming nodes in the proposed GNOA method. The simulation results show that the proposed GNOA method can reduce the required number of grooming nodes and decrease the cost of constructing a network to guarantee a certain request blocking probability when the wavelengths per fiber and transmitter/receiver ports per node are sufficient for the optical multicast in WDM networks.
      PubDate: Thu, 18 Feb 2016 10:47:48 +000
       
  • Physics of Internal Photoemission and Its Infrared Applications in the
           Low-Energy Limit

    • Abstract: Internal photoemission (IP) correlates with processes in which carriers are photoexcited and transferred from one material to another. This characteristic allows characterizing the properties of the heterostructure, for example, the band parameters of a material and the interface between two materials. IP also involves the generation and collection of photocarriers, which leads to applications in the photodetectors. This review discusses the generic IP processes based on heterojunction structures, characterizing -type band structure and the band offset at the heterointerface, and infrared photodetection including a novel concept of photoresponse extension based on an energy transfer mechanism between hot and cold carriers.
      PubDate: Thu, 28 Jan 2016 11:17:35 +000
       
  • Mathematical Verification for Transmission Performance of Centralized
           Lightwave WDM-RoF-PON with Quintuple Services Integrated in Each
           Wavelength Channel

    • Abstract: Wavelength-division-multiplexing passive-optical-network (WDM-PON) has been recognized as a promising solution of the “last mile” access as well as multibroadband data services access for end users, and WDM-RoF-PON, which employs radio-over-fiber (RoF) technique in WDM-PON, is even a more attractive approach for future broadband fiber and wireless access for its strong availability of centralized multiservices transmission operation and its transparency for bandwidth and signal modulation formats. As for multiservices development in WDM-RoF-PON, various system designs have been reported and verified via simulation or experiment till now, and the scheme with multiservices transmitted in each single wavelength channel is believed as the one that has the highest bandwidth efficiency; however, the corresponding mathematical verification is still hard to be found in state-of-the-art literature. In this paper, system design and data transmission performance of a quintuple services integrated WDM-RoF-PON which jointly employs carrier multiplexing and orthogonal modulation techniques, have been theoretically analyzed and verified in detail; moreover, the system design has been duplicated and verified experimentally and the theory system of such WDM-RoF-PON scheme has thus been formed.
      PubDate: Tue, 29 Dec 2015 11:36:15 +000
       
  • Target Tracking Algorithm Using Angular Point Matching Combined with
           Compressive Tracking

    • Abstract: To solve the problems of tracking errors such as target missing that emerged in compressive tracking (CT) algorithm due to factors such as pose variation, illumination change, and occlusion, a novel tracking algorithm combined angular point matching with compressive tracking (APMCCT) was proposed. A sparse measurement matrix was adopted to extract the Haar-like features. The offset of the predicted target position was integrated into the angular point matching, and the new target position was calculated. Furthermore, the updating mechanism of the template was optimized. Experiments on different video sequences have shown that the proposed APMCCT performs better than CT algorithm in terms of accuracy and robustness and adaptability to pose variation, illumination change, and occlusion.
      PubDate: Tue, 10 Nov 2015 07:06:20 +000
       
  • All-Optical Surface Micropatterning by Electric Field Intensity Gradient

    • Abstract: In this report an all-optical photo-induced formation of surface relief gratings is shown. For the surface patterning of As2S3 and As4S1.5Se4.5 films a direct holographic recording setup with a 532 nm wavelength Nd:YAG CW laser light was used. Our investigations have shown that the light-induced mass transfer process strongly depends on the material itself and on the polarization of the light. It has been shown that an electric field intensity gradient has to be obtained to achieve a direct patterning. The evolution of a surface relief in relation to recording parameters and thickness of the sample has been investigated in detail.
      PubDate: Thu, 05 Nov 2015 07:47:47 +000
       
  • Analysis of the Interference Modulation Depth in the Fourier Transform
           Spectrometer

    • Abstract: Based on the principle of the Michelson interferometer, the paper briefly describes the theoretical significance and calculates and deduces three expressions of the interference modulation depth. The influence of the surface shape error of plane mirror on modulation depth is analyzed, and the tolerance of error is also pointed out. Moreover, the dependence of modulation depth on the reflectance change of beam splitter interface is also analyzed, and the curve is given. It is concluded that this paper is of general significance for the Fourier transform spectrometer based on the principle of the Michelson two-beam interference.
      PubDate: Sun, 04 Oct 2015 16:34:22 +000
       
  • Effective Evaluation of the Noise Factor of Microchannel Plate

    • Abstract: To improve the noise performance of microchannel plate (MCP), we have presented a method using the sine random signals with Poisson distribution as the noise-excitation for electron source. By using this method, the effective evaluation of noise characteristics of MCP has been implemented through measuring and analyzing its noise factor. The results have demonstrated that the noise factor of filmed MCP is lower than 1.8. Additionally, as the open area ratio and the input electron energy are 72% and 400 eV, respectively, the noise characteristics of unfilmed MCP are improved evidently. Moreover, larger open area ratio, higher input electron energy, and higher voltage across the MCP all can reduce effectively the noise factor within a certain range. Meanwhile, the ion barrier film extends the life of image tube but at the cost of an increased noise factor. Therefore, it is necessary that a compromise between the optimum thickness of ion barrier film, open area ratio, input electron energy, and voltage across the MCP must be reached.
      PubDate: Thu, 27 Aug 2015 06:13:40 +000
       
  • Gain Incorporated Split-Ring Resonator Structures for Active Metamaterials

    • Abstract: We present a systematic study of split-ring resonator (SRR) structures that are used as the basic building blocks of active metamaterials with incorporated gain. The active split-ring resonator (aSRR) structures with gain elements can in theory have similar unusual electromagnetic responses such as negative effective permeability near their resonance of the artificial magnetic response just like their passive counterparts. At the same time aSRRs can have reversed imaginary part of the effective permeability and, therefore, mitigate the loss of passive SRRs. We explored in detail both passive and active SRRs through analytic theory, numerical simulations, and lab experimentation and demonstrated that aSRRs can have the similar negative effective permeability responses while reducing and even reversing the loss.
      PubDate: Wed, 26 Aug 2015 14:19:43 +000
       
  • Fivefold Symmetric Photonic Quasi-Crystal Fiber for Dispersion
           Compensation from S- to L-Band and Optimized at 1.55 μm

    • Abstract: A highly dispersive dual core quasi-periodic photonic crystal fiber is proposed for chromatic dispersion compensation. The dispersion for the dual concentric core fiber is optimized to compensate the chromatic dispersion with a high negative dispersion, accomplishing the communication bandwidth from S-band (1460 nm) to L-band (1625 nm). By precise control of structural parameter we have achieved a maximum dispersion of −18,838 ps/nm-km with the phase matching wavelength centred around 1.55 μm. We also numerically investigate the influence of structural parameter and doping effects and its response on peak dispersion parameter.
      PubDate: Mon, 03 Aug 2015 14:20:46 +000
       
  • Optimization of Multiband White-Light Illuminants for Specified Color
           Temperatures

    • Abstract: This paper describes an effective approach for the optimization of multiband spectra to produce prospective white-light spectra having specific color temperatures. The optimization process employs a genetic algorithm known as differential evolution, which aims to minimize the color rendering differences between a prospective white-light spectrum and its corresponding reference illuminant. Color rendering is assessed by calculating the CIEDE2000 color difference (ΔE00) for 14 CIE test colors under the two sources. Optimized white-light spectra were matched to three CIE standard illuminants, that is, A (2856 K), D50 (5003 K), and D65 (6504 K). Optimal solutions for three- and four-band 25 and 50 nm Gaussian spectra are presented and analyzed, together with mixed 4-LED spectra that were optimized in the same way. In all cases, the simulated sources were shown to provide color rendering of such quality that ΔE00av ≤ 2.24 units. Such white-light sources would likely find wide acceptance in numerous lighting applications.
      PubDate: Mon, 25 May 2015 11:10:53 +000
       
  • Block-Based Compressed Sensing for Neutron Radiation Image Using WDFB

    • Abstract: An ideal compression method for neutron radiation image should have high compression ratio while keeping more details of the original image. Compressed sensing (CS), which can break through the restrictions of sampling theorem, is likely to offer an efficient compression scheme for the neutron radiation image. Combining wavelet transform with directional filter banks, a novel nonredundant multiscale geometry analysis transform named Wavelet Directional Filter Banks (WDFB) is constructed and applied to represent neutron radiation image sparsely. Then, the block-based CS technique is introduced and a high performance CS scheme for neutron radiation image is proposed. By performing two-step iterative shrinkage algorithm the problem of norm minimization is solved to reconstruct neutron radiation image from random measurements. The experiment results demonstrate that the scheme not only improves the quality of reconstructed image obviously but also retains more details of original image.
      PubDate: Thu, 02 Apr 2015 14:11:34 +000
       
  • Unusual Blueshifting of Optical Band Gap of CdS Nanocrystals through a
           Chemical Bath Deposition Method

    • Abstract: CdS nanocrystals are synthesized through a chemical bath deposition method. After annealing, these nanocrystals are enlarged according to Scherrer’s formula. Small nanocrystals display wide band gaps as a result of the quantum effect experienced by nanocrystals of a certain size. However, the absorption edge and green and red emissions of annealed CdS nanocrystals show obvious blueshift compared with the as-grown ones. After annealing, the intensity ratio of these green and red emissions increases, which indicated that the defect states are reduced. Therefore, the improvement in crystalline quality and the reduced strain contribute to the unusual blueshifting of the optical band gap and of the green and red emissions.
      PubDate: Thu, 05 Mar 2015 12:04:57 +000
       
  • A Microring Temperature Sensor Based on the Surface Plasmon Wave

    • Abstract: A structure of microring sensor suitable for temperature measurement based on the surface plasmon wave is put forward in this paper. The sensor uses surface plasmon multilayer waveguiding structure in the vertical direction and U-shaped microring structure in the horizontal direction and utilizes SOI as the thermal material. The transfer function derivation of the structure of surface plasmon microring sensor is according to the transfer matrix method. While the change of refractive index of Si is caused by the change of ambient temperature, the effective refractive index of the multilayer waveguiding structure is changed, resulting in the drifting of the sensor output spectrum. This paper focuses on the transmission characteristics of multilayer waveguide structure and the impact on the output spectrum caused by refractive index changes in temperature parts. According to the calculation and simulation, the transmission performance of the structure is stable and the sensitivity is good. The resonance wavelength shift can reach 0.007 μm when the temperature is increased by 100 k and FSR can reach about 60 nm. This structure achieves a high sensitivity in the temperature sense taking into account a wide range of filter frequency selections, providing a theoretical basis for the preparation of microoptics.
      PubDate: Sun, 15 Feb 2015 09:13:17 +000
       
  • Performance of Series Connected GaAs Photovoltaic Converters under
           Multimode Optical Fiber Illumination

    • Abstract: In many military and industrial applications, GaAs photovoltaic (PV) converters are connected in series in order to generate the required voltage compatible with most common electronics. Multimode optical fibers are usually used to carry high-intensity laser and illuminate the series connected GaAs PV converters in real time. However, multimode optical fiber illumination has a speckled intensity pattern. The series connected PV array is extremely sensitive to nonuniform illumination; its performance is limited severely by the converter that is illuminated the least. This paper quantifies the effects of multimode optical fiber illumination on the performance of series connected GaAs PV converters, analyzes the loss mechanisms due to speckles, and discusses the maximum illumination efficiency. In order to describe the illumination dependent behavior detailedly, modeling of the series connected PV array is accomplished based on the equivalent circuit for PV cells. Finally, a series of experiments are carried out to demonstrate the theory analysis.
      PubDate: Sun, 21 Dec 2014 00:10:03 +000
       
  • Preparation of Compensation Ions Codoped SrTiO3:Pr3+ Red Phosphor with the
           Sol-Gel Method and Study of Its Luminescence Enhancement Mechanism

    • Abstract: SrTiO3:Pr3+ is the most representative titanate matrix red phosphor for field emission display (FED). The red luminous efficiency of SrTiO3:Pr3+ will be greatly improved after the compensation ions codoping, so SrTiO3:Pr3+ red phosphor has been a research focus at home and abroad. SrTiO3:Pr3+, SrTiO3:Pr3+, Mg2+, and SrTiO3:Pr3+, Al3+ phosphors are synthesized by a new sol-gel method. Crystal structure, spectral characteristics, and luminescence enhancement mechanism of the sample were studied by XRD and PL spectra. The results showed that after co-doped, SrTiO3:Pr3+ phosphor is single SrTiO3 cubic phase, the main emission front is located at 614 nm, corresponding to Pr3+ ions 1D23H4 transition emission. SrTiO3:Pr3+, Mg2+ and SrTiO3:Pr3+, Al3+ phosphor luminescence intensity is enhanced, but the main luminescence mechanism is not changed. Acceptor impurity = Mg2+, Al3+ will replace Ti bit after being doped into the crystal lattice to form charge compensation corresponding defect centers to reduce the demand of Sr2+ or Ti3+ vacancy. While Sr-doped Pr will make lattice distortion and transition energy of 4f-5d is very sensitive to crystal electric field changes around Pr atom. Doping different impurities will make electric field distribution around the icon have a different change. It increases energy transfer of 4f-5d transition and improves the luminous intensity of SrTiO3:Pr3+ red phosphor.
      PubDate: Sun, 14 Dec 2014 07:22:32 +000
       
  • Combination of Transverse Mode Selection and Active Longitudinal
           Mode-Locking of Broad Area Semiconductor Lasers

    • Abstract: Experimental results of the combination of transverse mode selection and active mode-locking with anti-reflection-coated broad area lasers (BALs) are presented. The BALs are subject to feedback from a free-space external Fourier-optical 4-setup with a reflective spatial frequency filter in the Fourier-plane for transverse mode selection. Driving the BALs with a high frequency modulated pump current above threshold active longitudinal mode-locking is achieved. Pulse durations as low as 88 ps are obtained, while the Gaussian-like fundamental or a higher order transverse mode up to mode number 5 is selected on purpose. Pulse duration and shape are nearly independent of the selected transverse mode.
      PubDate: Sun, 13 Jul 2014 00:00:00 +000
       
  • Signal Processing Algorithms for Down-Stream Traffic in Next Generation
           10 Gbit/s Fixed-Grid Passive Optical Networks

    • Abstract: We have analyzed the impact of digital and optical signal processing algorithms, that is, Volterra equalization (VE), digital backpropagation (BP), and optical phase conjugation with nonlinearity module (OPC-NM), in next generation 10 Gbit/s (also referred to as XG) DP-QPSK long haul WDM (fixed-grid) passive optical network (PON) without midspan repeaters over 120 km standard single mode fiber (SMF) link for downstream signals. Due to the compensation of optical Kerr effects, the sensitivity penalty is improved by 2 dB by implementing BP algorithm, 1.5 dB by VE algorithm, and 2.69 dB by OPC-NM. Moreover, with the implementation of NL equalization technique, we are able to get the transmission distance of 126.6 km SMF for the 1 : 1024 split ratio at 5 GHz channel spacing in the nonlinear region.
      PubDate: Sun, 22 Jun 2014 06:25:42 +000
       
  • Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

    • Abstract: We propose and design a spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and negative dispersion. The structure is designed using chalcogenide glass (As2S3) for different ellipticity ratios of air holes in the cladding and the effect on various properties is observed. The proposed structure has birefringence of the order 10−2, nonlinearity of 26739.42 W−1 m−1, and dispersion of −1136.69 at 0.85 μm. An accurate numerical approach based on finite element method is used for the design and simulation of the structure. Due to high birefringence and negative dispersion, the proposed structure can be used for polarization control and dispersion compensation, respectively.
      PubDate: Wed, 11 Jun 2014 12:21:07 +000
       
  • The CdS/CdSe/ZnS Photoanode Cosensitized Solar Cells Basedon Pt, CuS,
           Cu2S, and PbS Counter Electrodes

    • Abstract: Highly ordered mesoporous TiO2 modified by CdS, CdSe, and ZnS quantum dots (QDs) was fabricated by successive ionic layer adsorption and reaction (SILAR) method. The quantity of material deposition seems to be affected not only by the employed deposition method but also and mainly by the nature of the underlying layer. The CdS, CdSe, and ZnS QDs modification expands the photoresponse range of mesoporous TiO2 from ultraviolet region to visible range, as confirmed by UV-Vis spectrum. Optimized anode electrodes led to solar cells producing high current densities. Pt, CuS, PbS, and Cu2S have been used as electrocatalysts on counter electrodes. The maximum solar conversion efficiency reached in this work was 1.52% and was obtained by using Pt electrocatalyst. CuS, PbS, and Cu2S gave high currents and this was in line with the low charge transfer resistances recorded in their case.
      PubDate: Thu, 27 Feb 2014 11:06:56 +000
       
  • Design and Optimization of Polarization Splitting and Rotating Devices in
           Silicon-on-Insulator Technology

    • Abstract: We review polarization splitting and rotating photonic devices based on silicon-on-insulator technology platform, focusing on their performance and design criteria. In addition, we present a theoretical investigation and optimization of some rotator and splitter architectures to be employed for polarization diversity circuits. In this context, fabrication tolerances and their influences on device performance are theoretically estimated by rigorous simulations too.
      PubDate: Thu, 06 Feb 2014 09:25:09 +000
       
  • Burn-In Aging Behavior and Analytical Modeling of Wavelength-Division
           Multiplexing Semiconductor Lasers: Is the Swift Burn-In Feasible for
           Long-Term Reliability Assurance?

    • Abstract: Effective and economical burn-in screening is important for technology development and manufacture of semiconductor lasers. We study the burn-in degradation behavior of wavelength-division multiplexing semiconductor lasers to determine the feasibility of short burn-in. The burn-in is characterized by the sublinear model and correlated with long-term reliability.
      PubDate: Sun, 08 Dec 2013 09:46:16 +000
       
  • A Comprehensive Analysis of Plasmonics-Based GaAs MSM-Photodetector for
           High Bandwidth-Product Responsivity

    • Abstract: A detailed numerical study of subwavelength nanogratings behavior to enhance the light absorption characteristics in plasmonic-based metal-semiconductor-metal photodetectors (MSM-PDs) is performed by implementation of 2D finite-difference time-domain (FDTD) algorithm. Due to the structure design and changes in the device physical parameters, various devices with different geometries are simulated and compared. Parameters like nano-grating height and duty cycle (DC) are optimized for rectangular and taper subwavelength metal nanogratings on GaAs substrate and their impact on light absorption below the diffraction limits are confirmed. The calculated light enhancement is ~32.7-times for an optimized device in comparison with a conventional MSM-PD. This enhancement is attributed to the plasmonic effects in the near-field region.
      PubDate: Tue, 24 Sep 2013 11:15:18 +000
       
 
 
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