Optimisation d’un banc de mesure de bruit de phase additif dédié aux liaisons optiques-hyperfréquence de longueurs kilométriques

National audienc

Imagerie de Stokes à l'échelle du grain de speckle

National audienc

Optical nonlinearities in microwave photonic links

International audienc

Investigation expérimentale des distorsions électriques induites par les nonlinéarités optiques dans les liaisons optohyperfréquences kilométriques

National audienc

Polarimetric imaging beyond the speckle grain scale

International audienceWe address an experimental Stokes imaging setup allowing one to explore the polarimetric properties of a speckle light field with spatial resolution well beyond the speckle grain scale. We detail how the various experimental difficulties inherent to such measurements can be overcome with a dedicated measurement protocol involving a careful \emph{speckle registration} step. The setup and protocol are then validated on a metallic reference sample, and used to measure the state of polarization of light in each pixel of highly resolved speckle patterns ($>$2000 pixels per speckle grain) resulting from the scattering of an incident coherent beam on samples exhibiting different polarimetric properties. Evolution of the state of polarization with spatial averaging and across adjacent speckle grains is eventually addressed

Réalisation de mesures de bruit de phase additif dédiées aux liaisons optiques-microondes kilométriques.

National audienc

Terahertz Optoelectronic Down-Conversion and Phase-Locking Through Four-Wave Mixing

International audienceOptoelectronic down-conversion of a terahertz optical beatnote to a RF intermediate frequency is performed with a standard Mach-Zehnder modulator followed by a zero dispersion-slope highly nonlinear fiber. The two interleaved optical combs obtained by four-wave mixing are shown to contain more than 75 harmonics enabling to conveniently recover the phase noise of a beatnote at 770 GHz at ~500 MHz. This simple four-wave mixing assisted down-conversion architecture is implemented to a two-frequency solid-state laser in order to directly phase-lock its frequency difference. This is illustrated on a beatnote at 168 GHz directly phase locked to the local oscillator at 10 MHz

Buffer reservoir approach for cancellation of laser resonant noises

International audienc

Etude des nonlinéarités optiques sur les performances des liaisons optiques hyperfréquence.

National audienc