Amplitude Regeneration of Phase Encoded Signals using Injection Locking in Semiconductor Lasers

A phase preserving limiter based on injection locking in semiconductor lasers is experimentally investigated for 10Gb/s phase encoded signals. The proposed scheme exhibits significant amplitude noise squeezing in conjunction with extreme simplicity

Intermixed Time-Dependent Self-Focusing and Defocusing Nonlinearities in Polymer Solutions

[Image: see text] Low-power visible light can lead to spectacular nonlinear effects in soft-matter systems. The propagation of visible light through transparent solutions of certain polymers can experience either self-focusing or defocusing nonlinearity, depending on the solvent. We show how the self-focusing and defocusing responses can be captured by a nonlinear propagation model using local spatial and time-integrating responses. We realize a remarkable pattern formation in ternary solutions and model it assuming a linear combination of the self-focusing and defocusing nonlinearities in the constituent solvents. This versatile response of solutions to light irradiation may introduce a new approach for self-written waveguides and patterns

FWM-based wavelength conversion of 40 Gbaud PSK signals in a silicon germanium waveguide

We demonstrate four wave mixing (FWM) based wavelength conversion of 40 Gbaud differential phase shift keyed (DPSK) and quadrature phase shift keyed (QPSK) signals in a 2.5 cm long silicon germanium waveguide. For a 290 mW pump power, bit error ratio (BER) measurements show approximately a 2-dB power penalty in both cases of DPSK (measured at a BER of 10-9) and QPSK (at a BER of 10-3) signals that we examined

itanium mesh cranioplasty for patients with large cranial defects: Technical notes

We propose to describe some personal points of view concerning the repair of large cranial defects using titanium mesh, and in this sense we present few cases. Also we expose the presurgical planning by 3D imaging acquisition with the radiologic digital system which allow a computer aided design for a precise measurement of the shape and the curvature of cranial defect

Phase-encoded signal regeneration exploiting phase sensitive amplification

We discuss recent advances in phase-sensitive amplification technology and review its application to the regeneration of multi-level phase-encoded signals

Novel 60 GHz CPW array antennas with beam-forming features for indoor wireless over fiber networks

In this study two types of coplanar waveguide (CPW) array antennas are designed and analyzed for use in a 60GHz Radio over Fiber indoor network. The first one is based on high permittivity Rogers 6010 and Indium Phosphide (InP) substrates incorporating slots as radiating elements. The second one utilizes stacked geometry based on the above substrates. Both arrays present more 1 GHz bandwidth and 10dBi gain. Furthermore they can provide beam-forming operation by properly adjusting the signal's amplitude and phase. A Least Mean Square (LMS) algorithm is generated for this purpose and the radiation pattern is steered accordingly. At last, a photodiode is simulated using equivalent circuit and is adopted with the proposed arrays, and an optical beam forming scenario is discussed. © 2013 SPIE

Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

International audienceIn analogy to the study of critical phase transitions in statistical physics, it has been argued recently that the fracture of heterogeneous materials could be viewed as a critical phenomenon, either at laboratory or at geophysical scales. If the picture of the development of the fracture is correct one may guess that the precursors may reveal the critical approach of the main-shock. When a heterogeneous material is stretched, its evolution towards breaking is characterized by the appearance of microcracks before the final break-up. Microcracks produce both acoustic and electromagnetic(EM) emission in the frequency range from VLF to VHF. The microcracks and the associated acoustic and EM activities constitute the so-called precursors of general fracture. These precursors are detectable not only at laboratory but also at geophysical scales. VLF and VHF acoustic and EM emissions have been reported resulting from volcanic and seismic activities in various geologically distinct regions of the world. In the present work we attempt to establish the hypothesis that the evolution of the Earth's crust towards the critical point takes place not only in a mechanical but also in an electromagnetic sense. In other words, we focus on the possible electromagnetic criticality, which is reached while the catastrophic rupture in the Earth's crust approaches. Our main tool is the monitoring of micro-fractures that occur before the final breakup, by recording their radio-electromagnetic emissions. We show that the spectral power law analysis of the electromagnetic precursors reveals distinguishing signatures of underlying critical dynamics, such as: (i) the emergence of memory effects; (ii) the decrease with time of the anti-persistence behaviour; (iii) the presence of persistence properties in the tail of the sequence of the precursors; and (iv) the acceleration of the precursory electro-magnetic energy release. Moreover, the statistical analysis of the amplitudes of the electromagnetic fluctuations reveals the breaking of the symmetry as the theory predicts. Finally, we try to answer the question: how universal the observed electromagnetic critical behaviour of the failing system is

Radio-over-fibre technologies arising from the Building the future Optical Network in Europe (BONE) project

[EN] This study describes a wide range of salient radio-over-fibre system issues. Impulse radio and multiband ultra-wideband signal distribution over both single-mode fibre and multi-mode fibre (MMF) implementations are considered. Carrier frequencies ranging from 3.1 to 10.6 GHz, up to 60 GHz, are featured, and the use of microring laser transmitters is discussed. A cost-performance comparative analysis of competing distributed antenna system topologies is presented, and a theoretical approach to understanding the factors underlying radio-over-MMF performance for within-building applications is discussed. Finally, techniques to minimise thermal impacts on performance are described and novel energy-efficient schemes are introduced. Overall, this study provides a snap-shot of research being undertaken by European institutes involved in the Building the future Optical Network in Europe (BONE) project.The work described in this paper was carried out with the support of the EU-FP7 Network of Excellence BONE project.Parker, M.; Walker, SD.; Llorente, R.; Morant, M.; Beltrán, M.; Möllers, I.; Jäger, D.... (2010). Radio-over-fibre technologies arising from the Building the future Optical Network in Europe (BONE) project. IET Optoelectronics. 4(6):247-259. https://doi.org/10.1049/iet-opt.2009.0062S24725946http://www.ftthcouncil.euGomes, N. J., Morant, M., Alphones, A., Cabon, B., Mitchell, J. E., Lethien, C., … Iezekiel, S. (2009). Radio-over-fiber transport for the support of wireless broadband services [Invited]. Journal of Optical Networking, 8(2), 156. doi:10.1364/jon.8.000156Thakur, M. P., Quinlan, T. J., Bock, C., Walker, S. D., Toycan, M., Dudley, S. E. M., … Ben-Ezra, Y. (2009). 480-Mbps, Bi-Directional, Ultra-Wideband Radio-Over-Fiber Transmission Using a 1308/1564-nm Reflective Electro-Absorption Transducer and Commercially Available VCSELs. Journal of Lightwave Technology, 27(3), 266-272. doi:10.1109/jlt.2008.2005644ECMA-368 International Standard: ‘High rate ultra wideband PHY and MAC standard’, December 2008FCC 02-48: ‘Revision of part 15 of the commission's rules regarding ultra-wideband transmission systems’, April 2002ECC∕DEC∕(06)04: ‘On the harmonised conditions for devices using ultra-wideband (UWB) technology in bands below 10.6 GHz’, March 2006ETSI EN 302 065 V1.1.1 (2008-02): ‘Electromagnetic compatibility and radio spectrum matters (ERM); ultra wideband (UWB) technologies for communication purposes; harmonized EN covering the essential requirements of article 3.2 of the R&TTE Directive’, February 2008WiMedia Alliance: Worldwide regulatory status [online]. Available at: http://www.wimedia.orgMikroulis, S., Simos, H., Roditi, E., & Syvridis, D. (2005). Ultrafast all-optical AND logic operation based on four-wave mixing in a passive InGaAsP-InP microring resonator. IEEE Photonics Technology Letters, 17(9), 1878-1880. doi:10.1109/lpt.2005.853260Argyris, A., Hamacher, M., Chlouverakis, K. E., Bogris, A., & Syvridis, D. (2008). Photonic Integrated Device for Chaos Applications in Communications. Physical Review Letters, 100(19). doi:10.1103/physrevlett.100.194101Win, M. Z., & Scholtz, R. A. (1998). On the robustness of ultra-wide bandwidth signals in dense multipath environments. IEEE Communications Letters, 2(2), 51-53. doi:10.1109/4234.660801Flatman, A.: In-premises optical fibre installed base analysis to 2007. Presented at the IEEE 802.3 10GbE over FDDI Grade Fibre Study Group, Orlando, FL, March 2004Raddatz, L., & White, I. H. (1999). Overcoming the modal bandwidth limitation of multimode fiber by using passband modulation. IEEE Photonics Technology Letters, 11(2), 266-268. doi:10.1109/68.740725Hartmann, P., Xin Qian, Wonfor, A., Penty, R. V., & White, I. H. (2005). 1-20 GHz Directly Modulated Radio over MMF Link. 2005 International Topical Meeting on Microwave Photonics. doi:10.1109/mwp.2005.203548Kanprachar, S., & Jacobs, I. (2003). Diversity coding for subcarrier multiplexing on multimode fibers. IEEE Transactions on Communications, 51(9), 1546-1553. doi:10.1109/tcomm.2003.816981Gasulla, I., & Capmany, J. (2006). Transfer function of multimode fiber links using an electric field propagation model: Application to Radio over Fibre Systems. Optics Express, 14(20), 9051. doi:10.1364/oe.14.009051Al-Raweshidy, H., and Komaki, S.: ‘Radio over fiber technologies for mobile communication networks’, (Artech House 2002)Sauer, M., Kobyakov, A., & George, J. (2007). Radio Over Fiber for Picocellular Network Architectures. Journal of Lightwave Technology, 25(11), 3301-3320. doi:10.1109/jlt.2007.906822Gomes, N. J., Nkansah, A., & Wake, D. (2008). Radio-Over-MMF Techniques—Part I: RF to Microwave Frequency Systems. Journal of Lightwave Technology, 26(15), 2388-2395. doi:10.1109/jlt.2008.925624Rajan, G., Semenova, Y., Pengfei Wang, & Farrell, G. (2009). Temperature-Induced Instabilities in Macro-Bend Fiber Based Wavelength Measurement Systems. Journal of Lightwave Technology, 27(10), 1355-1361. doi:10.1109/jlt.2009.2014081Montalvo, J., Vázquez, C., & Montero, D. S. (2006). CWDM self-referencing sensor network based on ring resonators in reflective configuration. Optics Express, 14(11), 4601. doi:10.1364/oe.14.00460