Enhanced 10 Gb/s operations of directly modulated reflective semiconductor optical amplifiers without electronic equalization

We report enhanced 10 Gb/s operation of directly modulated bandwidth-limited reflective semiconductor optical amplifiers. By using a single suitable arrayed waveguide grating we achieve simultaneously WDM demultiplexing and optical equalization. Compared to previous approaches, the proposed system results significantly more tolerant to seeding wavelength drifts. This removes the need for wavelength lockers, additional electronic equalization or complex digital signal processing. Uniform C-band operations are obtained experimentally with < 2 dB power penalty within a wavelength drift of 10 GHz (which doubles the ITU-T standard recommendations)

Enhancing Resilience to Rayleigh Crosstalk by means of Line Coding and Electrical Filtering

We demonstrate a technique that ameliorates the performance of bidirectional systems impaired by in-band Rayleigh crosstalk, which is common in passive optical access networks based on centralized remote wavelength feeding. The technique is based on the combined use of a suitable line coding and ad hoc postdetection electrical filtering. Therefore, it can be seamless implemented in optical access systems and it is easily scalable with the data rate. We experimentally assess the technique by using a 8B10B coded 1.25-Gb/s signal. We report an increased tolerance to the signal-to-crosstalk ratio by about 5 dB

Multi-aspect visual analytics on large-scale high-dimensional cyber security data

In this article, we present a visual analytics system, SemanticPrism, which aims to analyze large-scale highdimensional cyber security datasets containing logs of a million computers. SemanticPrism visualizes the data from three different perspectives: spatiotemporal distribution, overall temporal trends, and pixel-based IP (Internet Protocol) address blocks. With each perspective, we use semantic zooming to present more detailed information. The interlinked visualizations and multiple levels of detail allow us to detect unexpected changes taking place in different dimensions of the data and to identify potential anomalies in the network. After comparing our approach to other submissions, we outline potential paths for future improvement. Copyright &amp;#169; 2013 The Author(s).close