Showing papers by "Jérôme Bourderionnet published in 2010"

Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

Abstract: We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

Collective phase measurement of an array of fiber lasers by quadriwave lateral shearing interferometry for coherent beam combining.

Abstract: We present a new configuration of quadriwave lateral shearing interferometer dedicated to phase detection for beam-combining purposes. Assuming that the fibers are disposed in a matrix arrangement, our scheme gives direct access to the phase step between adjacent fibers in two dimensions. Experimentally recorded interferograms are made only of two-wave interference fringes that scroll as the phase evolves in the fibers. This simplicity allows fast treatment by the spatial demodulation process, and the phase map from the fibers can be estimated in real time. No external reference is required, and the technique is fully compatible with a high number of fibers.

Experimental demonstration of enhanced slow and fast light by forced coherent population oscillations in a SOA

Abstract: We experimentally demonstrate enhanced slow and fast light by forced coherent population oscillations (CPOs) in a SOA. This approach is shown to rely on the interference between two different contributions. This opens the possibility to conceive a controllable RF phase shifter based on this set-up.

Experimental demonstration of enhanced slow and fast light by forced coherent population oscillations in a semiconductor optical amplifier.

Abstract: We experimentally demonstrate enhanced slow and fast light by forced coherent population oscillations in a semiconductor optical amplifier at gigahertz frequencies. This approach is shown to rely on the interference between two different contributions. This opens up the possibility of conceiving a controllable rf phase shifter based on this setup.

Intermodulation distortion in microwave phase shifters based on slow and fast light propagation in semiconductor optical amplifiers

Abstract: We show theoretically and validate experimentally the effect of filtering on the nonlinear behavior of slow and fast light links based on coherent population oscillations in semiconductor optical amplifiers. The existence of a dip in the power-versus-current characteristics for the fundamental frequency, as well as for the third-order intermodulation product, is clearly evidenced. These two dips occur at different bias currents. Their depths increase as the filtering strength of the red sideband is increased, and they completely vanish in the unfiltered case. Influence on the microwave photonics link is discussed.

90ps tunable true-time delay line based on photonic crystals

Abstract: A photonic crystal waveguide delay line is reported with 90ps of tunable delay over a 20GHz bandwidth. This corresponds to a maximum phase shift of 600°. The true-time delay characteristics are evidenced using a vector network analyzer.

Experimental demonstration of enhanced slow and fast light by forced coherent population oscillations in a SOA

Abstract: We experimentally demonstrate enhanced slow and fast light at GHz frequencies by forced coherent population oscillations (CPOs) in a SOA. This opens the possibility to conceive a controllable RF phase shifter based on this set-up.

Alternative architectures for RF phase shifters and optical delay lines based on slow and fast light in SOAs

Abstract: We show that forced coherent population oscillations (CPO) constitute an alternative set-up to conceive a controllable RF phase shifter, and that wave-mixing in SOAs opens the possibility to conceive optical tunable delay lines beyond the carrier lifetime limit.

Influence of optical filtering on nonlinearities in SOA-based slow and fast light microwave phase shifter

Abstract: We present an experimental and numerical investigation of the influence of filtering the red-shifted modulation on the linearity of a microwave-photonics link with a CPO-based phase shifter. Different behavior versus SOA bias current are evidenced.

Nonlinear distortion and spurious-free dynamic range of a tunable delay line based on slow light in SOA

Abstract: We developed a predictive model describing harmonic generation and intermodulation distortions in semiconductor optical amplifiers (SOAs). This model takes into account the variations of the saturation parameters along the propagation axis inside the SOA, and uses a rigorous expression of the gain oscillations harmonics. We derived the spurious-free dynamic range (SFDR) of a slow light delay line based on coherent population oscillation (CPO) effects, in a frequency range covering radar applications (from 40 kHz up to 30 GHz), and for a large range of injected currents. The influence of the high order distortions in the input microwave spectrum is discussed, and in particular, an interpretation of the SFDR improvement of a Mach-Zehnder modulator by CPOs effects in a SOA is given.