Flexible TWDM PON with WDM overlay for converged services

• Pluggable optical transceivers for TWDM PON:–Integrated OLT transceiver in enhanced CFP module.–Low cost ONU transceiver in SFP + module.
• Flexible TWDM PON architecture:–Provides pay-as-you-grow capability.–Facilitates dynamic wavelength and bandwidth allocation.–Achieves load balancing among different ODNs.–Allows dynamic power saving.–Support channel protection.
• TWDM PON with WDM overlay for converged services:–Unified access platform for residential, business and wireless applications.–Software defined flexible PON system for dynamic lambda flow, elastic bandwidth and flexible reach.

This paper reviews recent developments of flexible TWDM PON (time- and wavelength-division multiplexed passive optical network) with pluggable transceivers for pay-as-you-grow deployment, load balancing, channel protection and power saving. Different architectures for TWDM PON with WDM (wavelength division multiplexed) overlay for converged broadband services are discussed and experimental results are presented for WDM overlay using low-cost self-seeded RSOA (reflective semiconductor optical amplifiers). Challenging issues and possible solutions for future evolution toward software defined flexible PONs (FlexPONs) are also discussed with respect to dynamic lambda flow, elastic bandwidth and flexible reach.