Current Status of KAGRA

KAGRA is the fourth gravitational wave telescope that forms an international gravitational waves detection network with two Advanced LIGO and one Advanced Virgo telescopes. In addition to many sensitivity enhancement technologies that are generally utilized in these detectors, KAGRA introduces cryogenic technologies and low seismic noise underground environment that are both regarded as the possible technologies to realize the 3r d generation gravitational wave telescopes' sensitivities that are designed to be about 10 times better than the present gravitational wave telescopes. The KAGRA project has started in 2010, and the designed configuration of KAGRA was mostly finished in 2019 spring after several times operations as an interferometer with a simpler configuration in 2016 and 2018. Finally, KAGRA started its gravitational wave observation in 2020. At present, KAGRA is under improvement to obtain better sensitivity and stability to join the 4th international gravitational waves network detection with Advanced LIGO and Advanced Virgo from hopefully 2022.