He was involved in the LIGO project from its early days and worked on the 40m prototype interferometer at Caltech, suspension system, and advanced R&D for the LIGO project between 1989 and 1997. In 1997 he joined the TAMA project, the Japanese 300 meter interferometer for the detection of gravitational waves. As the leader of the detector group, he led TAMA to attain the world-best sensitivity at that time. In addition he initiated and has been in charge of the resonant sideband extraction experiment, quantum non-demolition experiment, super-high frequency gravitational wave detection, and displacement-noise-free interferometer. He also leads the Japanese space gravitational wave antenna DECIGO.