Fast OLT-protection method based on normal MPCP and backup wavelength pre-assignment on WDM/TDM-PONs [Invited]

This paper proposes a novel method for N:1 optical line terminal (OLT) protection on wavelength-division-multiplexing/time-division-multiplexing passive optical networks (WDM/TDM-PONs). The N:1 OLT protection scheme based on in-service wavelength tuning (λ-tuning) at optical network units (ONUs) provides reliable and cost-effective protection without the need for equipment specific to OLT protection on either the ONU or OLT side. Since the normal multipoint control protocol (MPCP) and backup wavelength pre-assignment are utilized, the proposed method significantly shortens the maximum protection time in N:1 OLT protection. Results of trials on a 40 Gbit/s (10 Gbit/s × 4 wavelengths) system with 40 km single mode fiber (SMF) transmission show service interruption times of less than 50 ms at all times, even with the practical -tuning time of 30 ms. The system trials also verify that the proposed method assures service interruption times of less than 50 ms, even with the split ratio on a PON of up to 512. These results verify that the proposed method is promising for next-generation multiservice convergence access networks.