423 Tbit/s, 18 Gbaud 64 QAM WDM coherent transmission over 160 km in the C-band using an injection-locked homodyne receiver with a spectral efficiency of 9 bit/s/Hz

We demonstrate a 235-channel wavelength division multiplexing (WDM), polarization-multiplexed (pol-mux) 18-Gbaud 64 QAM coherent transmission of 160 km over the full C-band. By applying an injection-locked homodyne detection circuit to WDM coherent transmission, we have achieved low noise optical carrier-phase locking between transmitted data and a local oscillator over the full C-band range. As a result, a potential capacity of 42.3 Tbit/s data with a spectral efficiency of 9 bit/s/Hz was transmitted.