43 research outputs found
Noise investigation of a dual-frequency VECSEL for application to Cesium clocks
We theoretically and experimentally study the noise of a class-A
dual-frequency vertical external cavity surface emitting laser operating at
Cesium clock wavelength. The intensity noises of the two orthogonally polarized
modes and the phase noise of their beatnote are investigated. The intensity
noises of the two modes and their correlations are well predicted by a theory
based on coupled rate equations. The phase noise of the beatnote is well
described by considering both thermal effects and the effect of phase-amplitude
coupling. The good agreement between theory and experiment indicates possible
ways to further decrease the laser noises
Fully-correlated pumping for dual-frequency VECSELs dedicated to cesium CPT clocks
We report a fully-correlated multi-mode pumping architecture optimized for
dramatic noise reduction of a class-A dual-frequency Vertical External Cavity
Surface Emitting Laser (VECSEL). Thanks to amplitude division of a laser diode,
the two orthogonally polarized modes emitted by the VECSEL oscillating at 852
nm are separately pumped by two beams exhibiting fully in--phase correlated
intensity noises. This is shown to lead to very strong and in-phase
correlations between the two lasing modes intensities. As a result, the phase
noise power spectral density of the RF beat note generated by the two modes
undergoes a drastic reduction of about 10 to 20 dB throughout the whole
frequency range from 10 kHz to 20 MHz and falls below the detection floor above
a few MHz. A good agreement is found with a model which uses the framework of
rate equations coupled by cross--saturation. The remaining phase noise is
attributed to thermal effects and additional technical noises and lies mainly
within the bandwidth of a phase-locked-loop
Ramsey CPT Signal Generation with a Miniature Clock Bench and a Dual-Frequency Optical Generator
We demonstrate, for the first time, Ramsey CPT spectroscopy with a miniature
electro-optical bench associated to a dual-frequency generator based on
combined optical injection locking and optical phase locking techniques
Preliminary results show Ramsey CPT resonance with a contrast of 2% at the
Cesium D2 line. Frequency difference locking loops lead to a contribution of
Dick effect to fractional frequency stability lower than 1.7x10-13 at 1 s, in
line with targeted clock stability of 5x10-13 at 1 s
Suppression of Nonlinear Interactions in Resonant Macroscopic Quantum Devices : the Example of the Solid-State Ring Laser Gyroscope
We study the suppression of nonlinear interactions in resonant macroscopic
quantum devices in the case of the solid-state ring laser gyroscope. These
nonlinear interactions are tuned by vibrating the gain medium along the cavity
axis. Beat note occurrence under rotation provides a precise measurement of the
strength of nonlinear interactions, which turn out to vanish for some discrete
values of the amplitude of vibration. Our theoretical description, in very good
agreement with the measured data, suggests the use of a higher vibration
frequency to achieve quasi-ideal rotation sensing over a broad range of
rotation speeds. We finally underline the analogy between this device and some
other macroscopic quantum rotation sensors, such as ring-shaped superfluid
configurations, where nonlinear interactions could be tuned for example by the
use of magnetically-induced Feschbach resonance
Génération d'impulsions solitoniques dans les fibres optiques par instabilité de modulation ou en cavité avec gestion de la dispersion, et caractérisation en intensité et en phase
DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF
Stabilisation of modelocking in fibre ring laser through pulse bunching
International audienc
Suppression of Nonlinear Interactions in Resonant Macroscopic Quantum Devices : the Example of the Solid-State Ring Laser Gyroscope
International audienceWe study the suppression of nonlinear interactions in resonant macroscopic quantum devices in the case of the solid-state ring laser gyroscope. These nonlinear interactions are tuned by vibrating the gain medium along the cavity axis. Beat note occurrence under rotation provides a precise measurement of the strength of nonlinear interactions, which turn out to vanish for some discrete values of the amplitude of vibration. Our theoretical description, in very good agreement with the measured data, suggests the use of a higher vibration frequency to achieve quasi-ideal rotation sensing over a broad range of rotation speeds. We finally underline the analogy between this device and some other macroscopic quantum rotation sensors, such as ring-shaped superfluid configurations, where nonlinear interactions could be tuned for example by the use of magnetically-induced Feschbach resonance
Laser power stabilization of a compact dual-frequency VECSEL for a cesium clock optical bench
International audienc
Laser power stabilization of a compact dual-frequency VECSEL for a cesium clock optical bench
International audienc