Ultra-High Performance Laser Source

The “Laser Source” is the subsystem generating and controlling the 14 laser signals needed for the optical interactions in the caesium tube.

It includes an optical bench and dedicated electronics. It allows obtaining and controlling all the required laser beams characteristics: spectral purity, high spectral and power stability, accurate frequency tuning, high polarisation ratio, etc…

Due to several mass and size constraints, the optical bench layout is very dense as it incorporates on both sides :

• 2 frequency stabilized Extended Cavity Diode Laser (ECDL) (with redundancy)
• 2 optically injected slave diode lasers (with redundancy)
• 7 shutter mechanisms
• 8 flux balance mechanisms
• 6 acousto-optic modulators
• 10 optical fibres

The ECDL has been developed specifically to meet the stringent spectral requirements such as stability, purity. The ECDL wavelength is accurately tuned to a saturated absorption ray of the caesium.

Slave Lasers are used to obtain more power for cooling atoms. Acousto-optic modulators, mechanisms, polarisation-maintaining fibres and a considerable amount of passive optical components are used in this subsystem.

The electronic subassembly contains 14 boards for the following functions:

• Power supply
• Digital control board
• Laser control boards
• Radio Frequency Synthesis board