Proof-of-principle Experimental Demonstration of Time-delay-interferometry for Chinese Space-borne Gravitational Wave Detection Missions

Due to the laser frequency fluctuation, the unequal arm-length of the laser interferometer will give rise to a significant phase noise. This laser frequency fluctuation noise dominates the current space-borne gravitational wave detection missions. To tackle this problem, a post data processing method called time delay interferometer was invented. This method was experimentally verified in the previous work with the scale of a few meters. By kilo-meter long optical fibers, an experimental verification of the time delay interferometer for Chinese space-borne gravitational wave detection mission was carried out in this work. The results showed that the laser frequency fluctuation noise could be suppressed by more than 6 orders in the frequency band from 1 mHz to 0.1 Hz