A microwave control system for continuous spatial-domain atom interferometers

We present a low-phase-noise microwave control system designed for spatial-domain atom interferometers, featuring the independent outputs of three microwave channels with minimal relative phase noise between them. Utilizing a nonlinear transmission line and single-sideband mixing with a digital signal source, we achieved three channels of 6835 MHz microwave frequency outputs, exhibiting absolute phase noises of −55, −100, and −124 dBc/Hz at 1 Hz, 1 kHz, and 1 MHz frequency offsets, respectively. We measured the relative phase noise between channels for a root mean square value of ∼251 μrad. A servo loop was integrated to stabilize the power ratio between Raman laser frequency components, ensuring long-term elimination of light shifts in the atom interferometer. The waveform parameters of the three microwave outputs can be adjusted independently, allowing for flexible manipulation of the atomic interference phase. These capabilities make the proposed microwave control system highly suitable for precise frequency and phase modulation in atom interferometer-based gyroscopes and accelerometers operating within continuous spatial-domain configurations.