OKI builds virtual PON network for 100-km demonstration

Current fiber-to-the-home (FTTH) networks based on current GE-PON systems provide a service range limited to 20 km. To address this issue, The National Institute of Information and Communications Technology (NICT) in 2009 commissioned OKI to initiate research on subscription-based broadband optical network technologies that would enable broadband services without installing new central offices, based on virtualized connections between optical line terminals and optical network units. With support from NTT, OKI connected NTT East Corp. buildings in Sapporo, Eniwa, and Chitose in Hokkaido with optical fiber and demonstrated the feasibility of a flexible optical access network in a test bed simulating a total transmission distance of 100 km for subscription-based broad optical networks.

“The adaptive network configuration technology developed by OKI combines OKI’s unique optical hybrid filtering (OHF) and adaptive networking technologies for flexible connections between OLT and ONU,” says Takeshi Kamijoh, general manager of the Research and Development Center at OKI. “In addition to wavelength-division multiplexing (WDM) used for metro-core networks, OHF realizes multiple expansion technology that enables ‘add/drop’ from 160-channel multiple signals by adding optical code division multiplexing (OCDM) technology, achieving filters with low transmission loss.”

Adaptive networking builds network infrastructure in a ring or cascade form by using centralized control node and passive OHF for the PON system, which was conventionally branched by power splitters. This enables broadband technology with lower loss resulting from branching. Centralized control nodes switch WDM and OCDM channel allocating, realizing virtual technology in a logical star form without depending on physical connection of OLT and ONU.

The experiment demonstrated the transmission of WDM and OCDM hybrid optical signals, restoration via passive routing, and service provisioning from GE-PON to 10G EPON without obstacles to other users.

Moving forward, OKI says it will continue to develop multi-channel control and OLT driving control technologies to offer more efficiency and build virtualized access system technology by combining this adaptive networking technology for an early practical realization for virtual PON system.