16 Gbit/s all-optical demultiplexing using four-wave mixing

A novel, purely optical technique for demultiplexing high-speed time-division multiplexed data is proposed and demonstrated. The technique uses optical fibre nonlinearity induced four-wave mixing with a data signal and a probe signal located at different wavelengths. Using only semiconductor laser light sources, 1:4 demultiplexing of 20 ps long, subpicojoule, 2/sup 15/-1 RZ pulses at a data rate of 16 Gbit/s with less than 1 dB penalty is demonstrated.<>     

Directional-hemispherical reflectance for spectralon by integration of its bidirectional reflectance

The directional-hemispherical reflectance is obtained for Spectralon, the material chosen for onboard radiometric calibration of the multiangle imaging spectroradiometer, at laser wavelengths of 442, 632.8, and 859.9 nm. With p- and s-polarized incident light and for an angle of incidence of 45 degrees , the bidirectional reflectance distribution function was measured over a polar angle range of 1-85 degrees and a range of azimuthal angles of 0-180 degrees in 10 degrees increments. The resultant directional-hemispherical reflectance is found by integration to be 1.00 ? 0.01 at 442 nm, 0.953 ? 0.01 at 632.8 nm, and 0.956 ? 0.01 at 859.9 nm. The experimental methodology and the data analysis are presented together with a full discussion of the primary experimental errors.     

Experience with the R-RDOT out-of-Step Relay

A new out-of-step relaying concept has been previously reported. The concept involves augmaenting apparent resistance (R) measurement with rate-of-change of apparent resistance (Rdot) computation. The new R-Rdot relay thus has more intelligence for control decisions. This follow-up paper presents the following new information: large scale simulation results, including use of relay outputs for discrete supplemental control action; additional details on design and testing of the microprocessor based relay; and experience during an extensive monitoring period at Malin Substation on the Pacific AC Intertie. The relay is now energized for initiating controlled separations at several locations within the Western North American Power System.     

On Two-Stage Sampling for Fixed-Width Interval Estimation of the Common Variance of Equi-Correlated Normal Distributions

Abstract

The present article presents two-stage procedures for fixed-width interval estimators of the common variance of equi-correlated normal distributions. This study is a continuation of those of Zacks and Ramig (1987 Zacks , S. and Ramig , P. ( 1987 ). Confidence Intervals for the Common Variance of Equicorrelated Normal Random Variables , in Contributions to the Theory and Applications of Statistics, A Volume in Honor of Herbert Soloman , New York : Academic Press . [Google Scholar]) and Ghezzi and Zacks (2005 Ghezzi , D. J. and Zacks , S. ( 2005 ). Inference on the Common Variance of Correlated Normal Random Variables , Communications in Statistics - Theory and Methods 34 : 1517 – 1531 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). We derive formulae for the distributions of total sample sizes and their functionals.     

All-Optical Network Consortium-ultrafast TDM networks

We describe recent results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks which is developing architectures, technology components, and applications for ultrafast 100 Gb/s time-division multiplexing (TDM) optical networks. The shared-media ultrafast networks we envision are appropriate for providing low-access-delay bandwidth on demand to both future high-burst rate (100 Gb/s) users as well aggregates of lower-rate users (i.e., a heterogeneous user population). To realize these goals we are developing ultrafast network architectures such as HLAN, described here, that operate well in high-latency environments and require only limited processing capability at the ultrafast bit rates. We also describe results on 80-Gb/s, 90-km soliton transmission, 100-Gb/s soliton compression laser source technology, picosecond short-pulse fiber ring lasers, picosecond-accuracy optical bit-phase sensing and clock recovery, all-optical injection-locked fiber figure-eight laser clock recovery, short-pulse fiber loop storage, and all-optical pulse width and wavelength conversion     

The surface structure and composition of the low index single crystal faces of the ordered alloy Pt3Sn

The surface composition and structure of 111, 100, and 110 oriented single crystals of the ordered alloy Pt₃Sn (Ll₂ or Cu₃Au-type) were determined using the combination of low energy electron diffraction (LEED) and low energy ion scattering spectroscopy (LEISS). The clean annealed surfaces displayed LEED patterns and Sn/Pt LEISS intensity ratios consistent with the surface structures expected for bulk termination. In the case of the 100 and 110 crystals, preferential termination in the mixed (50% Sn) layer was indicated, suggesting this termination to be the consequence of a thermodynamic preference for tin to be at the surface.     

Redesign and improved performance of the tropospheric ozone lidar at the Jet Propulsion Laboratory Table Mountain Facility

Improvements to the tropospheric ozone lidar at the Jet Propulsion Laboratory Table Mountain Facility for measurements of ozone profiles in the troposphere and lower stratosphere, between approximately 5-and 20-km altitude, are described. The changes were primarily related to the receiver optical subsystems and the data-acquisition system. The original 40-cm Cassegrain telescope was replaced with a faster (f/3) 91-cm Newtonian mirror. In the focal plane of this mirror, the lidar signal is divided into two parts by use of two separate optical fibers as field stops corresponding to different but neighboring 0.6-mrad fields of view. We then separate the two received wavelengths by aligning each transmitted beam to one of the fibers. In addition, two 50-mm telescopes are used for the collection of near-range returns. The four optical signals are brought to a chopper wheel for independent signal selection in the time and range domain. For each channel, an interference filter is used for skylight rejection and additional cross-talk prevention. The signals are detected with miniature photomultiplier tubes and input to a fast photon-counting system. The goals of these modifications were to increase the spatial and temporal resolution of the lidar, to extend the altitude range covered, to improve the quality of the raw data, and to enable regular and routine operation of the system for long-term measurements.     

Spaces for Creativity and Innovation in Two Established Organizations

Organizational work environments are increasingly strategically designed to support creativity and innovation processes, although a consistent theoretical frame for such an endeavour has not been developed yet. Creativity‐ and innovation‐oriented design of work environments requires an understanding of the principles of the underlying processes and their spatial implications. Both creativity and innovation processes are complex and display in different phases convergent and divergent characteristics. The processes are dependent on both individual and group effort. In this article these dimensions are discussed from a theoretical perspective and are used for evaluating the two cases presented here. The first case, the Interactive Creativity Landscape as integral part of the Fraunhofer Office Innovation Center in Germany has been designed interpreting the convergent and divergent phases of creative processes. The second case, the Learning Garden of a Scandinavian financial institution has been designed having de Bono's procedure in mind. The article concludes with the suggestion that increasingly organizations will offer diversity for spatially supporting creativity and innovation processes; solutions will be manifold but will follow certain principles – some of which are discussed here.