Optoelectronic oscillator with the microwave regenerative amplifier

International audienc

Measurement of the laser relative intensity noise

International audienceThis article describes the measurement of the RIN power spectral density with the cross-spectrum method. Averaging the cross spectrum of two equal and independent channels that measure the same beam, the instrument background is not limited by the single-channel noise. Additionally, the measure can be validated on the basis of simple mathematical properties. This removes the need of a low-noise beam to validate the instrument background, which is a relevant experimental limitation of the (traditional) single-channel method

Phase and frequency noise metrology

International audienceAs a consequence of a general trend in the physics of oscillators and clocks towards optics, phase and frequency metrology is rapidly moving to optics too. Yet, optics is not replacing the traditional radio-frequency (RF) and microwave domains. Instead, it adds tough challenges

Contribution of Laser Frequency and Power Fluctuations to the Microwave Phase Noise of Optoelectronic Oscillators

International audienceAn opto-electronic oscillator is a microwave oscillator in which the resonator is replaced with an optical fiber delay-line carrying an intensity-modulated laser beam. We consider the frequency and power fluctuations of a standard DFB telecom laser, and we investigate their effect on the phase noise of microwaves generated with opto-electronic oscillators. We propose a theoretical study showing how these two laser fluctuations are converted into phase noise in the output microwave. This theory predicts that the power noise should have a minor contribution to microwave phase noise, while the wavelength fluctuations should strongly contribute to phase noise via the chromatic dispersion of the few kilo-meters long optical fiber delay line. We have experimentally confirmed the validity of this theory by measuring the relative intensity noise and the optical frequency noise of a semiconductor laser, which has later been used for microwave generation. We show that the use of a zero-dispersion fiber delay-line can lead to a 10 dB improvement of the phase noise performance, relatively to the case were a standard single mode fiber is used

Compact optoelectronic oscillator using whispering gallery mode resonators for radio-frequency and millimeter wave generation

International audienceOptoelectronic oscillators are ultra-pure microwave generators based on optical energy storage instead of high finesse radio-frequency resonators. We present in this communication a new and compact architecture where the optical energy storage is performed by trapping laser light into the ultra-high Q whispering gallery modes of a millimeter-size disk resonator. As a proof of concept, we demonstrate the generation of a 10.7 GHz microwave with a phase noise of -110 dBrad(2)/Hz at 100 kHz. We also discuss in detail the potential of this architecture for the generation of microwaves with a frequency ranging from 50 to 200 GHz

Générateur de chaos optoélectronique à double retard pour les télécommunications optiques sécurisées à haut débits

Dans cet article sont présentés nos résultats d'investigations d'un système de cryptographie physique dédié aux télécommunications optiques sécuriséesà haut débits. Ce système est composé d'unémetteur et d'un récepteur du même type-clé cryptographique physique secrète-mettantà profit les propriétés des systèmes chaotiques continus, afin de sécuriser en temps réel des transmissions de données optiques par chaos. L'émetteur en question est un oscillateur optoélectroniqueà double retard, dont le fonctionnement s'appuie sur une dynamique non linéaireà délais ; il permet pratiquement de générer d'une manière contrôlée un chaos d'une grande complexité sur la variable intensité optique. L'élément clé de décodage réside dans la capacité du système récepteur a reproduire le plus fidèlement possible les oscillations chaotiques de l'émetteur, autrement dit la synchronisation entre chaos, en vue de restituer avec une bonne qualité l'information utile noyée par modulation chaotique au niveau de l'émetteur