Stacked TDM-PON with colorless ONU for NG-PON

Current passive optical networks (PONs) (Gigabit PON (GPON) and Ethernet PON (EPON)) will run out of bandwidth sooner or later due to the ever increasing bandwidth demand. The aforementioned and the new next generation PON stage 1 (NG-PON1) standards (10 Gigabit-PON (XG-PON) and 10 Gigabit Ethernet-PON (10G-EPON)) are based on time division multiplexing (TDM-PON), which has its limitations such as limited bandwidth. In this paper, stacked TDM-PON architecture with four wavelengths for each direction, that is compatible with currently deployed optical distribution networks (ODNs), is proposed to meet the requirements of NG-PON stage 2 (NG-PON2). The proposed architecture has colorless optical network units (ONUs) by generating the upstream wavelengths at the optical line terminal (OLT). Four laser diodes (LDs) at the OLT for the upstream transmission are enough for all ONUs, instated of having LD or optical transmitter at each ONU, which makes a colorless and cost-effective ONU. A good performance is observed for 40 Gb/s downstream transmission and 10 Gb/s upstream transmission.