Interaction between laser phase-locking and laser pointing for a space gravitational wave interferometer

We have conducted both theoretical and experimental investigations into the interaction between laser phase-locking and laser pointing techniques, which are crucial for space gravitational wave detection missions. Both techniques are essential for minimizing phase noise in the space interferometer, as the laser phase is the carrier of gravitational wave information. Introducing phase noise from either technique can significantly degrade the mission’s performance. To date, both techniques have been studied independently. Our research reveals the interaction that the laser phase-locking technique is sensitive to the laser pointing technique. The laser phase-locking technique suppresses one phase information from the quadrant photo diode (QPD) and disrupts the differential wave sensing (DWS) function for the laser pointing technique. Such circumstances indicate a need for re-evaluation of the current designs for both techniques.