80Gbit/s (5.3Gbit/s 16WDM) signal transmission has been successfully a
chieved by using installed 1130km long submarine cable. The measured v
alue of the Q factor is 17.8dB, on average. This system is designed fo
r both single channel transmission and future WDM transmission. These
results will be useful for system design considering future capacity u
pgrading by WDM technology.