Study the phase transient of the RF Mach-Zehnder interferometric switch

The traditional switch exhibits phase discontinuity and transients in few hundreds microradian which will induce the larger microwave leakage shift in the atomic fountain clock. The RF Mach-Zehnder interferometric switch is developed in order to decrease the phase variations without inducing phase discontinuity. To detect the phase variations, the phase transient measurement system is also built and described in detail in this paper. The result shows the peak to peak phase variations of RF Mach-Zehnder interferometric is 10 microradians within the measurement resolution of a few microradians after five days averaging.