Abstract
This paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial wireless microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate wireless microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered wireless microphones.

Abstract
Reflective semiconductor optical amplifier (RSOA) is considered a strong candidate to play an important role in realizing the next generation wavelength division multiplexing passive optical network, based on the wavelength reuse concept. Therefore, an accurate and efficient modeling of RSOA is of significant importance. We present a time-domain wideband model for simulation of spatial and temporal distribution of photons and carriers in a bulk RSOA. We provide a novel approach for efficient amplified spontaneous emission modeling, considering a tradeoff between the accuracy and the computational efficiency. The multiobjective genetic algorithm is utilized for parameter extraction. Experimental validation has been performed for continuous wave input, non-return to zero (NRZ) on-off keying, and quadrature phase-shift keying (QPSK) signaling pulses up to 40 Gb/s of bit rate, in both amplification and remodulation regimes. We further present systematic performance evaluation under remodulation scenario. Saturation, noise, chirp, and signal broadening are successfully predicted, while reducing the computational time compared to other wideband models.

Abstract
TV White Spaces technology is a means of allowing wireless devices to opportunistically use locally-available TV channels (TV White Spaces), enabled by a geolocation database. The geolocation database informs the device of which channels can be used at a given location, and in the UK/EU case, which transmission powers (EIRPs) can be used on each channel based on the technical characteristics of the device, given an assumed interference limit and protection margin at the edge of the primary service coverage area(s). The UK regulator, Ofcom, has initiated a large-scale Pilot of TV White Spaces technology and devices. The ICT-ACROPOLIS Network of Excellence, teaming up with the ICT-SOLDER project and others, is running an extensive series of trials under this effort. The purpose of these trials is to test a number of aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white spaces devices, among others. An additional key purpose is to undertake a number of research investigations such as into aggregation of TV White Space resources with conventional (licensed/unlicensed) resources, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper describes our trials, their intentions and characteristics, objectives, and some early observations.

Abstract
This paper proposes a new methodology for the generation of quadrature amplitude modulation signals, based on all-optical processing from nonlinear interferometric devices. The degradation of the systems performance is numerically analyzed, as a function of operational parameter's unbalance and physical impairments of the system. The results shows that the probe laser power and the coupling factor of optical couplers are the most sensitive parameters of the proposed format conversion system.

Abstract
TV White Spaces (TVWS) technology allows wireless devices to opportunistically use locally-available TV channels enabled by a geolocation database. The UK regulator Ofcom has initiated a pilot of TVWS technology in the UK. This paper concerns a large-scale series of trials under that pilot. The purposes are to test aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white space devices, among others. An additional key purpose is to perform research investigations such as on aggregation of TVWS resources with conventional resources and also aggregation solely within TVWS, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper provides an update on the trials, giving an overview of their objectives and characteristics, some aspects that have been covered, and some early results and observations.

Abstract
Over the years, the increased search and exchange of information lead to an increase of traffic intensity in todays optical communication networks. Coherent communications, using the amplitude and phase of the signal, reappears as one of the transmission techniques to increase the spectral efficiency and throughput of optical channels. In this context, this paper present a survey on format conversion of modulated signals using MZISOAs, based exclusively on all-optical techniques through wavelength conversion. We also present two proposal using all-optical techniques: One for the conversion of amplitude modulation signals to a continuous phase modulation format, and another technique for the conversion of OOK signals to QPSK and QAM signals. Both approaches are experimentally validated.