Optical Interconnects Could Lead to All-Optical Data Center Switches

By Lisa Huff

On-board interconnects have for some time just been handled with copper traces, but with data rates now reaching beyond 10G, this is ripe for change. In fact, it is already changing; evidenced by the big splash IBM and Avago Technologies made at this year's OFC/NFOEC conference. The computer giant and transceiver manufacturer teamed to develop what they are calling "the fastest, most energy-efficient embedded interconnect technology of its kind."

Deemed the MicroPOD™, Avago developed it for IBM's next generation supercomputer, POWER7™. While it was designed for HPC server interconnects, it could be used for on-board or chip-to-chip interconnects as well. The devices use a newly designed miniature detachable connector from US CONEC called PRIZM™ LightTurn™. The system has separate transmitter and receiver modules that are connected through a 12-fiber ribbon. Each lane supports up to 12.5 Gbps. It uses 850nm VCSEL and PIN diode arrays. The embedded modules can be used for any board-level or I/O-level application by either using two PRIZM LightTurn connectors or one PRIZM LightTurn and one MPO.

While these modules are currently for the HPC market, Avago designed something very similar for Intel and its Light Peak interconnect system  for what some are calling “optical USB.” MicroPOD is targeted at high-density environments so a natural extension of its market reach would be into switches and routers. The market for such devices probably will not become huge in the next few years, but it is exciting to see that companies in this space have started to spend R&D dollars again and that there are at least a few customers willing to employ the technology right out of the gate. Of course, it must be noted that this project was partially funded by DARPA.

But this technology MUST be too expensive for the typical piece of network equipment right? Not so, says Avago, because the manufacturing process is 100-percent automated and with Avago's vertical integration, the prices (at volume) may actually be able to rival those of today's transceivers. I’ll hold judgment until Avago proves it can win more than one big customer, however, I think MicroPOD holds the promise to change the paradigm for on-board, board-to-board and even network-element-to-network-element optical interconnects.