We demonstrate 20 Gsymbol/s, 256 QAM polarization multiplexed (pol-mux) 320 Gbit/s coherent transmission. By employing an LD-based injection locking circuit, we achieved low noise optical carrier-phase locking between the LO and the data signal. Furthermore, frequency domain equalization and digital back-propagation enabled us to realize precise compensation for transmitted waveform distortions. As a result, a 320 Gbit/s data was successfully transmitted over 160 km with a potential spectral efficiency of 10.9 bit/s/Hz. This is the highest symbol rate yet achieved in a pol-mux 256 QAM coherent transmission. In addition, we also describe a pol-mux 256 QAM transmission at a symbol rate of 10 Gsymbol/s.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics