Semiconductor Optical Amplifier-based Laser System for Cold-Atom Sensors

An array of emerging instruments seeks to use laser-cooled atoms as precision sensors. The potential impact of these technologies, such as atom interferometer gravimeters and Rydberg-atom RF-electric probes, can be greatly enhanced if cold-atom systems can be adapted from laboratory-scale experiments to compact, low-power field deployable instruments. However, existing setups typically require bulky and power-hungry laser and optics systems (LOS) to prepare, control, and interrogate the atomic system using a variety of frequency-referenced and rapidly reconfigurable laser beams. In this work, we investigate the feasibility of using semiconductor optical amplifiers (SOAs) to replace high-power pump lasers and acousto-optic modulators within a simple atom cooling apparatus. We find that existing off-the-shelf SOA components operating at relevant wavelengths for Cs and Rb atom cooling (852 and 780 nm, respectively) are able to permit an attractive combination of rapid (sub-microsecond) high extinction ratio ($>$65 dB) switching while acting as power boosters prior to the atomic physics package. Combined with custom-designed and fabricated drive electronics, we implement a simple all-semiconductor laser and amplifier LOS for atom cooling, and demonstrate power sequencing and active stabilization of a bank of SOAs used for cooling of a cloud of neutral Cs atoms. The entire module, including reference and cooling laser subsystems and control electronics, totals DC power consumption of around 13.5 W. These results indicate the feasibility of all-semiconductor laser systems for future low-power field and flight-deployable cold-atom sensor instruments.