High-purity microwave signal from a dual-frequency semiconductor laser for CPT atomic clocks (poster)

Paul Dumont (1) , Fabiola Camargo (1) , Patrick Georges (1) , Gaëlle Lucas-Leclin (1) , Jean-Marie Danet (2) , David Holleville (2) , Stéphane Guérandel (2) , Grégoire Pillet (3) , Ghaya Baili (3) , Loic Morvan (3) , Daniel Dolfi (3) , Iryna Gozhyk (1, 4) , G. Beaudoin (4) , Isabelle Sagnes (4)

1 Laboratoire Charles Fabry / Lasers
2 SYRTE - Systèmes de Référence Temps Espace
3 Thales Research and Technology [Palaiseau]
4 LPN - Laboratoire de photonique et de nanostructures

Coherent population trapping (CPT) of metal-alkali atoms is an interesting technique for the development of compact atomic frequency references; it relies on the excitation of the atoms by two phase-coherent laser fields. We describe the design and operation of an innovating dual-frequency laser source dedicated to Cs CPT atomic clocks, based on the direct dual-frequency and dual-polarization operation of an optically-pumped semiconductor laser at 852 nm. The phase noise of beatnote generated by the laser source is at maximum of -90 dBrad²/Hz with active stabilization, and the relative intensity noise (RIN) has been measured at -115 dB/Hz. It would potentially results in a clock frequency stability of 1.6 .10^-12 at 1 second, limited by the laser RIN. With proper adjustments in the laser and clock set-up, we target a stability of 3.10^-13 at 1 second.

Keywords: Dual-frequency lasers; Phase noise; Phase noise.; Atomic clocks; Coherent population trapping; Vertical external cavity surface emitting lasers

Domains: Optics [physics.optics]

Paul Dumont, Fabiola Camargo, Patrick Georges, Gaëlle Lucas-Leclin, Jean-Marie Danet, et al.. High-purity microwave signal from a dual-frequency semiconductor laser for CPT atomic clocks (poster). European Frequency & Time Forum, Jun 2014, Neuchâtel, Switzerland. ⟨hal-01074037⟩