100G PAM-4 PON with 34 dB Power Budget Using Joint Nonlinear Tomlinson-Harashima Precoding and Volterra Equalization

Real-Time DSP-Free 100 Gbit/s/λ PAM-4 Fiber Access Link Using EML and Direct Detection

“…SOA1 has a small signal gain of 28 dB, a saturation input power of -16 dBm at 1 dB gain compression and a noise figure (NF) of 7 dB at 1309 nm wavelength, for bias current of 444 mA at 20°C. In our previous work [12], to avoid nonlinear effects during fiber propagation, the launched power had to be limited to 12 dBm [9]. We thus add an attenuator before the SOA to reduce the input power to -17 dBm and obtain a Tx output power of 12 dBm (Fig.…”

“…However, few reports [8] real time demonstrations due to the development cost of customized digital signal processing (DSP) chips at this bitrate. On the other hand, 100 Gbit/s with 4-level Pulse Amplitude Modulation (PAM-4) has been demonstrated with direct detection (DD) and offline DSP [9][10][11][12]. In [13], we showed that using a Mach-Zehnder Modulator (MZM) and DD, PAM-4 could be detected without DSP.…”

Overview of high-speed TDM-PON beyond 50 Gbps per wavelength using digital signal processing [Invited Tutorial]

“…DSP techniques to counteract the effect if non-linearities, such as preand post-equalizers based on VNLE [42], neural networks (NN) [43] or NL Tomlinson-Harashima precoding (THP) [44], to mention some popular approaches, have been proposed. Simplified ad-hoc solutions to deal with NL distortion, such as polynomial functions [45] and look-uptables [46] have been also analyzed.…”

“…Using VNLE and SQRT was shown to achieve a gain of 3 dB and 1.3 dB against FFE/DFE, respectively. In [44], a PAM-4 system with a power budget of 34 dB in O-band is demonstrated using a DML with a launch power of 13 dBm. NL THP at transmitter and 2nd order VNLE at RX are used.…”