Demonstration of 200 Gbit/s Single λ Dual Band DMT Transmission With a SE of 6.29 bit/s/Hz

With the increasing demand of bandwidth, a higher capacity communication system is required for short-reach optical link. Intensity modulation/direct detection (IM-DD) is considered as a reasonable method, due to its low cost and power consumption. In the aspect of digital signal processing (DSP), discrete Fourier transform-spread (DFT-s) precoding can be used to reduce peak to average power ratio (PAPR) and average the noise among the subcarriers. In addition, probabilistic shaping (PS) turns out to further increase the system capacity. We experimentally demonstrated a 200 Gbit/s single λ dual band DMT transmission with a spectrum efficiency (SE) of 6.29 bit/s/Hz. The achievable information rate (AIR) of the proposed dual band signal increases about 30 Gbit/s compared with that of single band signal. Moreover, single-sideband (SSB) signal and signal with guard band are implemented to mitigate the frequency selective fading of optical fiber chromatic dispersion (CD). The performance of these two methods are quite closed for short reach transmission. Considering the signal-signal beat interference (SSBI) introduced by the SSB signal, an extra Volterra filter is applied in DSP. Besides, an extra optical filter is required to generate the SSB signal.