Multi-channel phasemeter and its application in the heterodyne laser interferometry

The mission to detect gravitational wave in space requires a not only sophisticated but also ultra-precise laser interferometric measurement system. Within a single spacecraft, tens of interferometric beat signals are generated at the same time and they also need to be processed simultaneously. In this paper, a multi-channel phasemeter which can parallelly process the signals is constructed. The test shows that a sensitivity of 2 pi mu rad/aeHz could be achieved in the frequency range of 0.1 to 10 Hz. We also utilize the phasemeter to evaluate the performance of a heterodyne laser interferometer