2,867 research outputs found
Hybrid WDM/SCMA-PON using wavelength-locked Fabry-Perot laser diodes
No full textWe propose a large-capacity hybrid passive optical network (PON) with a wavelength-sharing technique achieved by applying subcarrier multiple access on each single channel of a wavelength-division-multiplexed (WDM) PON. We also use forward-error correction to reduce the effect of optical beat interference noise. We demonstrate three-subchannel sharing in a 100-GHz-spaced WDM-PON to accommodate three times more subscribers simultaneously at a fully dedicated connection rate of 125 Mb/s.This work
was supported in part by the National Research Laboratory (NRL) Program of
the Ministry of Science and Technology (MOST)
Broad-band light source using mutually injected Fabry-Perot laser diodes for WDM-PON
No full textWe propose and demonstrate a new broad-band light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON) based on the wavelength locked Fabry-Perot laser diodes (F-P LDs). By mutual injection between two antireflection-coated F-P LDs, we realized a broad-band light with a low relative intensity noise. By using the proposed BLS for wavelength locking of the F-P LD, we achieve color-free operation of the optical network termination with Manchester coded data. We also demonstrate a WDM-PON based on the proposed BLS.Thisworkwas
supported by the Korea Ministry of Science and Technology under the National
Research Laboratory
Color-free operation of dense WDM-PON based on the wavelength-locked Fabry-Perot laser diodes injecting a low-noise BLS
No full textWe demonstrate color-free operation of a dense wavelength-division-multiplexing passive optical network based on the wavelength-locked Fabry-Perot laser diodes with injection of a low-noise broadband light source (BLS). The color-free operation, i.e., wavelength-independent operation, was obtained at 50-GHz channel spacing with the help of a narrow injection bandwidth of the low-noise BLS. We also demonstrate three-channel upstream transmission with 100-Mb/s Manchester coded data.This
work was supported by the Korea Ministry of Science and Technology under
the National Research Laboratory
Surfactant-free hydrothermal synthesis of highly tetragonal barium titanate nanowires: A structural investigation
No full textBarium titanate nanowires synthesized with a surfactant-free hydrothermal method have been characterized by various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), synchrotron X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM and SEM analyses show the uniform cylindrical nanowires. The Rietveld refinement with synchrotron X-ray powder diffraction showed that the lattice parameters of cubic and tetragonal phases were a (= b = c) = 4.0134 angstrom and a (= b) = 3.9998 angstrom, c = 4.0303 angstrom, respectively. The final weighted R-factor, R-wp, was 6.75% and the goodness of fit indicator was 1.30. The mass fraction of tetragonal and cubic phases based on the refined scale factor for the two phases were 98.4% and 1.6%, respectively, which clearly show the nanowires are tetragonal. The XPS analysis has shown that as-obtained BaTiO3 nanowires were phase pure. The Raman spectra confirm the tetragonal phase of the BaTiO3 nanowires. The dielectric constant measurement shows the shift in the transition temperature (T-c = 105 degrees C) compared to the bulk transition temperature (T-c = 132 degrees C). The dielectric constant at T-c was 174 measured at 1 kHz frequencyclose75808
Wavelength self-managed optical WDM source using, polarization-multiplexed Fabry-Perot laser diodes
No full textWe propose and demonstrate a novel wavelength self-managed optical source for access networks. By polarization multiplexing with two Fabry-Perot laser diodes, we can largely reduce wavelength and polarization dependence on the injected amplified spontaneous emission (ASE) light. The worst case power penalty incurred by the wavelength detuning can be decreased within 1 dB. We can obtain not only increased signal power and signal-to-noise ratio but also widened operation range. Even though polarized ASE light is used, data transmission is possible using the proposed source. Therefore, the proposed source is very practical to use in low-cost optical wavelength-division-multiplexing access networks
Intensity noise suppression and 1.25 Gb/s transmission using a wave-length locked Fabry-Perot laser diode with filtered ASE injection
No full textAnalysis of penalty due to low-frequency intensity modulation in optical transmission systems
No full textThe low-frequency intensity modulation in optical transmission systems can occurred by optical performance monitoring or dynamic devices such as acoustooptic tunable filters. Using a conventional receiver model, we derived the optical signal-to-noise ratio (OSNR) and Q penalties due to the low-frequency intensity modulation. The penalty is a function of the extinction ratio, OSNR, the modulation index, and the number of pilot-tone signals. The analytic results show good agreement with the experimental results
Strong in-plane magnetic anisotropy in (111)-oriented CoFe2O4 thin film
No full textThe perfect (111)-oriented CoFe2O4 thin films were grown on Pt(111)/Si substrate by pulsed laser deposition technique at substrate temperature of 600 degrees C. The optimum oxygen pressure was found to be 10 mTorr based on structural and magnetic properties. The film grown at 10 mTorr has the highest (111)orientation degree and magnetization. The films are under in-plane tensile stress due to the residual thermal strain which is thickness-dependent. It was found that the (111)-oriented CoFe204 thin film demonstrates the strong in-plane magnetic anisotropy which results from orientation as well as the stress-induced magnetic anisotropy. (C) 2013 Elsevier B.V. All rights reserved.X1127sciescopu
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