Development of Yb Optical Lattice Clock to 10−17 Uncertainty Level and a New Clock Laser System at KRISS

The systematic uncertainty of the Yb optical lattice clock has been improved to 8.3×10
^-17
at KRISS, and the absolute frequency has been measured with uncertainty of 9.6×10
^-16
referenced to the SI second (TT). We also describe future prospects to further reduce the systematic uncertainty and the absolute frequency measurement uncertainty. A new clock laser system has been developed to evaluate the uncertainties in reasonably short time.