Single Carrier 400G Transmission With Single-Ended Heterodyne Detection

We demonstrate single channel 448 Gb/s (56 GBaud) and wavelength division multiplexed (WDM) 1.792-Tb/s transmission of Nyquist polarization division multiplexed 16-ary quadrature amplitude modulation (16-QAM) signal by employing heterodyne detection with single-ended photodiodes. The signal-signal beat interference induced by square-law detection of the single-ended photodiodes is overcome by the Kramers-Kronig scheme. For both single channel 160-km standard single mode fiber (SSMF) transmission and WDM 80-km SSMF transmission, the bit-error rates are below the 7% hard-decision forward error correction threshold of 4.5 × 10^-3. To the best of our knowledge, this letter is the first experiment of single carrier 400G optical transport with heterodyne detection. For WDM operation of high symbol rate heterodyne system, a record net spectral efficiency of 5.71 b/s/Hz is achieved.