Recent Developments In European Union Crisis Management Operations

The European Union (EU) has the possibility to plan, establish, and launch crisis management operations on the basis of Articles 42(4) and 43(2) of the Treaty on European Union (TEU).\u2

Improvement of optical signal-to-noise ratio of a high-power pump by stimulated Brillouin scattering in an optical fiber

We propose and demonstrate improvement of optical signal-to-noise ratio of a highpower pump by saturated stimulated Brillouin amplification of a backward seed in a fiber. A 27-dB improvement was obtained for a 1-W pump

Pump-to-signal transfer of low-frequency intensity modulation in fiber optical parametric amplifiers

This paper describes the theoretical and experimental investigation of the transfer of low-frequency intensity modulation (IM) from pump to signal in fiber optical parametric amplifiers (OPAs). It is first established that low-frequency IM of the pump remains unchanged over the length of the amplifier in spite of the presence of parametric gain. The pump-power dependence of the OPA gain is then used to calculate the instantaneous effect of pump IM on the signal and idler output powers. These calculations are performed for both one- and two-pump OPAs. The main predictions are that 1) the ratio ρ of the signal intensity modulation depth to that of the pump varies across the OPA gain spectrum and 2) for a 20-dB gain, ρ can exceed 10 at some wavelengths, which indicates that this effect can be detrimental. Experiments have been performed to verify these predictions. Using sinusoidal IM of the pump, the resulting amplified signal IM was measured, and the experimental results were found to be in good agreement with the theoretical predictions. © 2005 IEEE.published_or_final_versio

Ultrafast and versatile spectroscopy by temporal Fourier transform

published_or_final_versio

Transmission of optical communication signals by distributed parametric amplification

We have demonstrated, for the first time to our knowledge, distributed parametric amplification, i.e. amplification of 10-Gb/s communication signals along a 75-km transmission fiber by using a co-propagating pump with only 66.5 mW of power.published_or_final_versio

Recent advances in the design and implementation of practical fiber optical parametric amplifiers

Conference on Optoelectronic and Microelectronic Materials and Devices, Brisbane, Australia, 8-10 December 2004Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler can grow together if pump power is high enough, and phase matching occurs. In recent years, impressive performance has been demonstrated in several respects: 1) Gain in excess of 60 dB has been obtained; 2) fiber OPAs can exhibit a large variety of gain spectra: a gain bandwidth of 400 nm has been demonstrated; tunable narrowband gain regions can also be generated; 3) Noise figure of 3.7 dB, limited by other third-order nonlinear process; 4) Polarization-insensitive operation in both one-pump and two-pump configurations; 5) The presence of the idler can be used for wavelength conversion. Also, the spectrum of the idler is inverted with respect to that of the signal; thus by placing an OPA in the middle of a fiber span one can realize mid-span spectral inversion (MSSI) which counteracts the effect of fiber dispersion and some nonlinear effects. Besides using fiber OPA in continuous-wave regime as in typical systems, pulsed-pump has also been demonstrated to achieve larger bandwidth and higher peak gain by combining with optical filtering technique. Furthermore, by modulating the pump it is possible to modulate signal and/or idler at the output. This can be used to implement a variety of signal processing functions, including: fast signal switching; demultiplexing of time-division-multiplexed signals; retiming and reshaping of waveforms; optical sampling. A number of challenges must be overcome in order for fiber OPAs to be useful in communication applications. In multi-wavelength systems, these are: four-wave mixing, cross-phase modulation; and cross-gain modulation between signals. Furthermore, the pump-to-signal relative intensity noise (RIN) transfer and frequency/phase modulation (FM/PM) to signal intensity conversion are also potential challenges for practical fiber OPAs. © 2005 IEEE.published_or_final_versio

Normality and rupture in some Argentinian authors of comics: Muñoz, Sampayo, Breccia and Nine

A partir de las obras de tres dibujantes de historietas y de un guionista argentinos recientemente publicadas en Francia (Muñoz y Sampayo 2004; Nine, Sfar y Trondheim 2004; Breccia 2003), me propuse observar lo que sucede hoy con las grandes rupturas respecto de la historieta tradicional. Me refiero con ello a los tres estilos mundiales: la línea clara europea, el cómic americano y el manga japonés. En efecto, estas tres corrientes, más allá de sus especificidades, comparten un cierto número de funcionalidades. Por razones prácticas, he decidido estudiar estos aspectos según el principio metodológico del análisis estratificado de Anne-Marie Houdebine (1994)

Ultra-flat wideband single-pump Raman-enhanced parametric amplification

We experimentally optimize a single pump fiber optical parametric amplifier in terms of gain spectral bandwidth and gain variation (GV). We find that optimal performance is achieved with the pump tuned to the zero-dispersion wavelength of dispersion stable highly nonlinear fiber (HNLF). We demonstrate further improvement of parametric gain bandwidth and GV by decreasing the HNLF length. We discover that Raman and parametric gain spectra produced by the same pump may be merged together to enhance overall gain bandwidth, while keeping GV low. Consequently, we report an ultra-flat gain of 9.6±0.5 dB over a range of 111 nm (12.8 THz) on one side of the pump. Additionally, we demonstrate amplification of a 60 Gbit/s QPSK signal tuned over a portion of the available bandwidth with OSNR penalty less than 1 dB for Q2 below 14 dB