Design and performance test of the spaceborne laser in the TianQin-1 mission

Zhu Li, Huizong Duan, Xiangqing Huang, Min Ming, Peibo Liu, Shu Zou, Guanfang Wang, Xian Zhang, Minglin Yang, Bin Cao, Qi Liu, Shanqing Yang, Liangcheng Tu, and Hsienchi Yeh

Abstract: TianQin-1 is a mission in the TianQin project, which uses a single satellite to demonstrate the maturity of the key technology for the space-based gravitational wave detection. The spaceborne laser in the TianQin-1 mission consists of a self-developed DBR one and a commercial RIO one. The DBR laser is also developed as a pumping source for the main NPRO laser in the final solution of TianQin. The two lasers were mutual backups and both passed the environment performance verification. The on ground results showed that the self-developed DBR laser could provide a stable output of 18 mW with a drift of 0.6 mW/h. Meanwhile, the internal temperature was controlled at the mK level. The results of in-orbit experiments show that the DBR laser works well as a direct source of the laser interferometer. The overall displacement resolution and the noise floor of the interferometer was approximately 25 pm and 30 pm/ at 0.1 Hz, respectively, better than the goals of the TianQin-1 mission.