112.5 Gbit/s long reach passive optical network with over 31 dB power budget enabled by semiconductor optical amplifiers

We experimentally demonstrate the downstream transmission of 112.5 Gbit/s pulse amplitude modulated (PAM) signals in the O-band for future time-division multiplexed long-reach passive optical networks (LR-PONs). For the first time, this work demonstrates the use of a commercial quantum-well semiconductor optical amplifier (QW-SOA) in the remote node (RN) of a 100G-class PON to extend the transmission distance between the optical line terminal and the optical network unit. Besides, we discuss the performance of a QW-SOA in amplifying uniform and probabilistically shaped (PS) continuous-mode downstream PAM signals, such as PAM-4, PAM-8, and PS-PAM-8, and also discuss its potential during upstream burst-mode operations. Considering the hard-decision low-density parity-check bit error ratio limit of 1 × 10 − 2 , the optical power budgets of 32.85 dB and 31.3 dB are achieved for the downstream PAM-4 and PS-PAM-8 signals, respectively, using a truncated T-spaced Volterra nonlinear equalizer after 112.5 Gbit/s SOA-amplified transmissions over a 50 km single-mode fiber, satisfying the class N2 power budget requirement of 31 dB for PONs. To the best of our knowledge, this is the highest power budget ever reported for 100G-class LR-PON with 50 km optical reach employing a commercial QW-SOA in the RN of a PON.