Linearity performance analysis of the differential wavefront sensing for the Taiji programme

Abstract

The Taiji programme is a Chinese space-based laser interferometer gravitational wave detection mission and the differential wavefront sensing (DWS) technique is introduced to reduce the effect of the laser pointing noise. As the distance between two adjacent satellites is about (Formula presented.), the wavefront of the receiving beam is a flat top beam. In this paper, we construct an analytical model of the DWS signal under the circumstances of Gaussian beam-flat top beam interference and study the linearity performance. The position offset of the beams is found to greatly affect the linearity range. A numerical method is used to simulate the linearity range of the DWS signal under various operating conditions. The linearity range decrease with the increase of the offset angle of the Gaussian beam and the offset length of the flat top beam. The offset range of the beams based on the requirement of the Taiji is given at last.