Ultra-high-capacity DWDM transmission system by multilevel modulations and digital coherent detection

In this paper, we will report our latest experimental results. These includes 20 times 112-Gb/s PDM-RZ-QPSK transmission over 1540-km of standard single mode fiber (SSMF), a record capacity of 17 Tb/s within the C-band optical bandwidth (4.025 THz) over 660 km of ultra-low-loss fiber using 161 times 114-Gbps PDM-RZ-8PSK formats, and hybrid 10 times 112 Gb/s PDM-RZ-QPSK and 10 times 44 Gb/s PDM-NRZ-QPSK transmission with 25-GHz channel spacing over 1600 km of SSMF.