Abstract
Burst loss is a critical issue in Optical Burst Switching (OBS) networks which restrains its deployment. This article presents a novel routing and wavelength assignment strategy for the Cooperative Clustered OBS (C2OBS) network architecture, to proactively avoid contention. In C2OBS, the network topology is divided into several manageable overlapping zones/clusters, with a Zone Head (ZH) node keeping an information base of zone resources. The ZH pre-computes a list of alternate k-shortest disjoint paths for every ingress-egress node pair within the zone. The ZH utilizes both the inferred knowledge about wavelength usage at the zone intermediate nodes and a novel poles apart heuristic for assigning wavelengths to incoming bursts. A route is selected among the pre-computed paths where the selected wavelength is available. As a result, traffic is balanced among the set of pre-computed routes, thus proactively reducing probability of contention. This strategy is called Resource Aware Routing (RAR) and Intelligent Wavelength Assignment (IWA).

Abstract
In this work, an in-depth analysis concerning the transmission performance of IEEE802.11g/n WiFi signals in a radio-over-fiber system is presented. Low-cost optical/electrical transceivers based on 850 nm vertical cavity surface emitting lasers (VCSELs) and PIN photodiodes are considered. System modelling includes the impact of noise generated in the optical path, such as relative intensity noise (RIN), shot noise, photodetector thermal noise, clipping and intermodulation distortion. Analytic results based on Volterra series analysis for the performance of the system in terms of SNR and EVM for several optical modulation index values are obtained. The theoretical analysis is also compared with experimental results. Among several conclusions, it is observed that the laser intermodulation distortion, clipping and RIN are the most relevant factors.

Abstract
This article analyzes experimentally the limitations observed in a 45 km Raman amplified 4 x 40 Gb/s transmission system operating under multiple pump and single high pump power configurations. A signal-to-noise ratio of 19.2 dB, an extinction ratio of 10.4 dB and a jitter of 1097 fs are achieved for moderate pump powers and higher order stimulated Brillouin scattering lines give rise to system degradation for pump power levels more than 0.5 W. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:14031407, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26827

Abstract
We propose the use of inverse scattering on the design of ultra wide band nonuniform coupled line directional couplers with a specified coupling response. The inverse scattering is performed using the layer peeling algorithm which is simple and of easy implementation as a computer routine. To validate the method a wide band directional coupler is designed and implemented. © 2012 IEEE.

Abstract
This study aims to design a compact two antennas array on a USB dongle for WLAN 5.8 GHz application (IEEE 802.11n). The proposed antenna adopts an Inverted-L antenna (ILA) structure, which can be easily integrated into an industry product. The two antenna elements are closely spaced and the high isolation between them is achieved by using the neutralization technique. Moreover, the impedance matching of both antennas is improved by introducing one vertical stub on the neutralizing line. In this way, both the isolation between the two antennas and the impedance matching of each antenna can be improved simultaneously. The experimental results show that this antenna has wide operation bandwidth (S11 <-10 dB) from 5.7 to more than 6 GHz with isolation always better than 10 dB. © 2012 IEEE.

Abstract
The Daphne project has been addressing the adoption of an optical fiber infrastructure for future aircrafts. Beyond the obvious motivation of reduced weight and electromagnetic interference, the availability of a huge amount of bandwidth makes the optical fiber well suited to transport Radio Frequency (RF) signals transparently, while avoiding cumbersome dedicated RF cabling. An integrated optical network may be exploited to transport radio signals from diverse aircraft antennas ranging from satellite/earth communications, collision avoidance, GPS signals for positioning and attitude determination, weather/detection RADAR to corrosion sensors. Such network can also support passenger infotainment and mobile communication services, such as cellular GSM/UMTS/LTE, broadband Wi-Fi (IEEE 802.11) and Ultra-Wide-Band Wimedia/WiGig. Specifically, the optical fiber infrastructure may provide connectivity from external antennas (through remote nodes) to RF transceivers installed in the cockpit and avionics bay (head-end nodes); in the context of the present paper, the transmission of differential GPS signals used to provide aircraft attitude information will be discussed. The use of GPS for aircraft attitude determination has been under discussion for more than 20 years [1]. It consists in performing carrier-phase differential processing of measurements from GPS antennas affixed to the frame of the aircraft, which yields centimeter- or millimeter-level accuracies, provided that integer phase ambiguities are resolved [2]. The attitude algorithm consists in a highly accurate real time kinematic (RTK) technique, given the short baseline distance between antennas, in which the main antenna acts as a Base station and two auxiliary antennas as Rovers. In the present experiment, we used a setup consisting of two-antennas (Base and Rover), which is enough to evaluate the RTK performance. A particular aspect of concern stems from the fact that the transmission of optical signals through a complex optical fiber network is subject to the occurrence of reflections in the multitude of connectors spanning the path between a remote node and a head-end node. Therefore, we will focus our analysis on the performance impact of optical reflections affecting the power level stability of the optical source. © 2012 IEEE.