Avago Technologies is now delivering to customers its 120 Gigabit-per-second optical engine devices.
Such a parallel optics design offer several advantages when used on a motherboard. It offer greater flexibility when cooling since traditional optics are normally in pluggable slots at the card edge, furthest away from the fans. Such optical engines also simplify high-speed signal routing and electromagnetic interference issues since fibre is used rather than copper traces.
Avago has two designs – the 8x8mm MicroPod and the 22x18mm MiniPod. The 12x10.3125 Gigabit-per-second (Gbps) MicroPods are being used in IBM’s Blue Gene computer and Avago says it is already shipping tens of thousands of the devices a month.
“The [MicroPod’s] signal pins have a very tight pitch and some of our customers find that difficult to do,” says Victor Krutul, director of marketing for the fibre optics division at Avago Technologies. The MiniPod design tackles this by using the MicroPod optical engine but a more relaxed pitch. The MiniPod uses a 9x9 electrical MegArray connector and is now sampling, says Avago.
Figure 1 shows 14 MiniPod optical engines on a board, each operating at 12x10Gbps. “If you were trying to route all those signals electrically on the board, it would be impossible,” says Krutul. All 14 MiniPods go to one connector, equating to a 1.68Tbps interface.
Figure 2 shows 16 MicroPods in a 4x4 array. “Those [MicroPods] can get even closer,” says Krutul. Also shown are the connectors to the MicroPod array. Avago has worked with US Conec to design connectors whereby the flat ribbon fibres linking the MicroPods can stack on top of each other. In this example, there are four connections for each row of MicroPods.