To expand the submarine transmission capacity, higher OSNR is important. Higher OSNR can be realized by advanced optical fibers having low transmission loss and low nonlinearity. We successfully realized the lowest transmission loss of 0.1419 dB/km at 1560 nm wavelength. It was the first time to realize a 0.14 dB/km in 50 years history of silica-based optical fiber. This epoch-making result was enabled by reducing Rayleigh scattering. In addition, microbending loss was kept low using a new soft inner coating in spite of a 147μm<sup>2</sup> large effective area. This achievement will contribute to further expansion of submarine transmission capacity.