Experimental Demonstration of Four-Channel WDM 560 Gbit/s 128QAM-DMT Using IM/DD for 2-km Optical Interconnect

In this paper, we experimentally demonstrated a four-channel wavelength-division-multiplex (WDM) 560 Gbit/s 128 quadrature amplitude modulation (128QAM)-Discrete MultiTone (DMT) signal transmission in a short reach interconnect. Coordinated discrete Fourier transform-spread and preequalization are jointly used to simultaneously overcome serious frequency domain power attenuation and reduce the peak-to-average power ratio of the DMT signal. An additional postdecision-directed least mean square equalizer is used afterward to further compensate the channel response and mitigate the devices' implementation penalty. These proposed algorithms and equalizer are validated through experiment in this paper, we achieved the highest capacity signal transmission in the four-channel WDM transmission system using intensitymodulation and directdetection over a 2.4-km single mode fiber with a bit-error-ratio under the hard-decision forward error correction limit of 3.8 × 10
^-3
.