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. Index Terms-Cesium clock, dual-frequency laser, intensity noise, phase noise, vertical external cavity surface emitting laser.