Polarization multiplexing and hybrid modulation based bandwidth efficient NG-PON2 coexisting with GPON and XG-PON

Abstract

Bandwidth efficiency is an important design parameter for next-generation passive optical network stage 2 (NG-PON2). In this paper, two optical line terminal (OLT) designs based on the polarization split state are proposed for NG-PON2. The first method doubles the data rate per wavelength by separate amplitude modulation of both polarization states, whereas, in the second method, differential phase-shift keying (DPSK) modulates another data stream on each amplitude-modulated state; this approach increases the data rate per wavelength fourfold. The proposed system provides NG-PON2 access while coexisting with a gigabit passive optical network (GPON) and 10 GPON (XG-PON). The proposed system design serves 1024 NG-PON2 opitcal network units (ONUs), 128 GPON ONUs, and 128 XG-PON ONUs. The transmission performance of the system is verified by evaluating the bit error rate (BER) for varied received power. An acceptable BER level of less than ${{1}}{{{0}}^{- 9}}$ is considered in this work.