1,721,124 research outputs found
1545NM-pumped long-wavelengh-band erbium-doped fiber amplifier with enhanced power conversion efficiency
No full textHigh-gain coefficient long-wavelength-band erbium-doped fiber amplifier using 1530-nm band pump
No full textA 1530-nm band has been studied as pump wavelength for long-wavelength-band erbium-doped fiber amplifier (L-band EDFA). The pump source is built using a tunable light source and cascaded conventional-band (C-band) EDFA, The L-band EDFA uses a forward pumping scheme. Within the 1530-nm band, 1545-nm pump demonstrates 0.45-dB/mW gain coefficient, which is twice better than that of conventional 1480-nm pumped EDFA, The noise figure of 1530-nm pump is at worst 6.36 dB, which is 0.75 dB higher than that of 1480-nm pumped EDFA. Such high-gain coefficient indicates that the L-band EDFA consumes low power
Performances of erbium-doped fiber amplifier using 1530nm-band pump for long wavelength multichannel amplification
No full textThe performance of a long wavelength-band erbium-doped fiber amplifier (L-band EDFA) using 1530nm-band pumping has been studied, A 1530nm-band pump source is built using a tunable light source and two C-band EDFAs in cascaded configuration, which is able to deliver a maximum output power of 23dBm, Gain coefficient and noise figure (NF) of the L-band EDFA are measured for pump wavelengths between 1530nm and 1560nm, The gain coefficient with a 1545nm pump is more than twice as large as with a 1480nm pump. It indicates that the L-band EDFA consumes low power, The noise figure of 1530nm pump is 6.36dB at worst, which is 0.75dB higher than that of 1480mn pumped EDFA. The optimum pump wave-length range to obtain high gain and low NF in the 1530nm band appears to be between 1530nm and 1540nm. Gain spectra as a function of a pump wavelength have bandwidth of more than 10nm so that a broadband pump source can be used as 1530nm-band pump, The L-band EDFA is also tested for WDM signals, Flat Gain bandwidth is 32nm from 1571.5 to 1603.5nm within 1dB excursion at input signal of -10dBm/ch, These results demonstrate that 1530nm-band pump can be used as a new efficient pump source for L-band EDFAs
Effects of compositional and structural change on the corrosion behaviour of nitrogen implanted Zircaloy-4
No full textThe influence of nitrogen implantation on the corrosion behaviour of Zircaloy-4 was examined by potentiodynamic polarization tests in a chloride and an acid solution, and the results were discussed with structural and compositional variations of implanted layer that was determined by X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The resistance to localized corrosion of Zircaloy-4 was very sensitive to the ion dose and the substrate temperature during the implantation. At substrate temperatures above 200 degrees C, the pitting potential of the nitrogen implanted alloy in deaerated 4 M NaCl at 80 degrees C increased gradually with the ion dose from 350 mV(SCE) for the unimplanted sample to 990 mV(SCE) for the alloy implanted with an ion dose of 6 x 10(17) ions cm(-2), and then the alloy was immune to pitting when implanted with ion doses greater than about 1 x 10(18) ions cm-2. In contrast to this, the alloy implanted at 100 degrees C exhibited an inferior corrosion resistance to the unimplanted sample irrespective of the ion dose. A drastic increase in the resistance to pitting corrosion in chlorides as well as a significant reduction in the passive current density in acid solution of the implanted alloy, were found to be associated with the formation of ZrN layer with a stoichiometric ratio of N to Zr. The low resistance to localized and general corrosion of the alloy implanted at 100 degrees C was attributed to the increase in structural defects produced by ion bombardment, and to low atomic mobility in the implanted layer. (C) 1999 Elsevier Science S.A. All rights reserved
Interfacial layer properties of HfO2 films formed by plasma-enhanced atomic layer deposition on silicon
No full textThe interfacial oxide layers, generated on Si substrates during the initial stage of HfO2 atomic layer deposition (ALD), have been investigated depending on the oxygen reactants, oxygen plasma and water. In the plasma-enhanced ALD (PEALD) using oxygen plasma, a 2-nm-thick interfacial layer, which was intermixed with Hf-Si-O and SiO2 having a dielectric constant (k) of 6.5, was formed, while water made a 1.5-nm-thick interfacial layer composed mainly of SiO2. Additionally, by utilizing oxygen plasma, the k of the HfO2 film itself was increased up to 22.2 resulting in a higher effective k, and a much lower leakage current density was also obtained. (c) 2006 The Electrochemical Society.This work was supported by the project of Brain Korea 21(BK21).
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
An all-optical gain-controlled amplifier for bidirectional transmission
No full textA novel all-optical gain-controlled (AOGQ bidirectional amplifier is proposed and demonstrated in a compact structure. The AOGC function using fiber Bragg grating (FBG) pairs controls both directional signals independently, and combinations of optical interleavers and isolators suppress Rayleigh backscattering (RB) noise. The amplifier achieves high and constant gain with a wide dynamic input signal range and low noise figure. The performance does not depend on the input signal conditions, whether static-state or transient signals, or whether there is symmetric or asymmetric data traffic on bidirectional transmission. Transmission comparison experiments between invariable symmetrical and random variable asymmetric bidirectional data traffic verify that the all-optical gain control and bidirectional amplification functions are successfully combined into this proposed amplifier.I wish to thank the Photonics Research Laboratory, in the
Department of Electrical and Electronic Engineering, The
University of Melbourne, Australia, for their help
320km optical transmission using EDFA and Raman amplifier for 10Gbit/s 128 channel DWDM signals
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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