ZTE Unveils Next-Gen PON Prototype

AMSTERDAM - Network equipment provider ZTE Corporation unveiled a time- and wavelength-division multiplexing passive optical network (TWDM-PON) prototype along with a solution for building pay-as-you-grow, flexibly evolving, green fiber-to-the-home networks on which a range of technologies coexist.

Most of today's fiber access networks use time-division multiplexing, in which a single wavelength on a fiber is divided into multiple time slots and each time slot is allotted to a different subscriber. Wavelength-division multiplexing, which uses multiple fiber wavelengths and can potentially dedicate an entire wavelength to a single subscriber, is also available but not yet widely used. TWDM uses a combination of time-division multiplexing and wavelength-division multiplexing.

Over the next five years, ZTE expects FTTH deployers to use GPON (today's dominant standard, supporting 2.5 Gbps downstream and 1.25 Gbps upstream) and XGPON1 (the newest standard available, which supports 10 Gbps downstream and 2.5 Gbps upstream). Both of these standards rely on time-division multiplexing. When operators need to reach higher bandwidths in the future, they will tap into more of the fiber's wavelengths, using the TWDM technology shown today.

The Full Service Access Network (FSAN) Group, an industry association that guides the development of passive optical networking standards, designated TWDM-PON as the main direction for the next generation of passive optical networking technology. ZTE developed its first TWDM-PON prototype soon after the standards direction was determined.

Peaceful Coexistence of PON Standards
The central-office equipment for ZTE's TWDM-PON prototype enables the coexistence of GPON, XG-PON1, NG-PON2 and WDM-PtP standards on the same platform and easy upgrading from one standard to another. The customer-premises equipment consists of colorless optical network terminals with receivers and transmitters that can be tuned to any incoming wavelength of light.

“Operators need to be building broadband networks that can evolve flexibly,” says Bei Jinsong, director of ZTE Optical Access Networks. “Taking this approach, current networks that use GPON and XG-PON1 technologies, including FTTP, FTTH, FTTdp, can meet network development requirements for the next five to 10 years. Over that period, neither existing XG-PON1 nor the optical network infrastructure needs to be changed. ... By overlaying XG-PONs with new wavelengths, the network can gradually upgrade to the bandwidth of NG-PON2 as needed or enable open access based on wavelength paths.”

Bei adds, “The concept also supports expanding through WDM-PtP to provide services such as backhaul, fronthaul, business access, etc. As a result, it is able to help operators markedly reduce expenditure on network construction and energy consumption, thus effectively protecting their investments.”