IBM Switches on the Light For High-Speed Data Transfers

IBM is ready to light up data transfers over long distances between computers with a new chip that could ultimately spell the end for slower electrical wiring.
After a decade of research, IBM has developed a new silicon photonics chip that can transfer data at aggregate speeds of 100Gbps (bits per second). In tests, the reference chip could transfer data using pulses of light over a distance of two kilometers.
Light can transfer data faster than copper cables, which are used in data centers to link storage, networking and servers in data centers. The silicon photonics chip could aid in introducing high-bandwidth optical fiber connections in future generations of supercomputers and servers, especially with vast amounts of data moving between computing resources.
IBM is developing the technology with the intent to push it in data centers, and it won’t be in PCs or handhelds anytime soon, said Wilfried Haensch, senior manager of IBM’s Silicon Photonics Group.
The silicon photonics technology could also fundamentally change the way servers are implemented in data centers by decoupling the processing, memory and storage units into separate boxes. The design could help applications run faster and reduce component costs by consolidating fans and power supplies.
There is also demand for more computing power in servers with applications like analytics, machine learning and big data. Optical connections could help dozens of processors communicate on a server rack, making it easier to break up processes over multiple resources, said Richard Doherty, research director at The Envisioneering Group.
Optical connections could make servers much like storage drives, which can be easily hot-swapped depending on processing needs in data centers, Doherty said.
Light is already being used for long-distance data transfers over telecom networks, but that technology can be expensive. Optical cables are also available for the Thunderbolt interconnect, which is used in Macs and PCs for high-speed data transfers with external peripherals.
IBM’s silicon photonics technology is meant for shorter distances, and is cheaper than optical technology used in telecom networks, Haensch said.
Intel has also made silicon photonics chips for data centers but has struggled to ship them on time. IBM may not be the first with a silicon photonics chip, but its technology is more viable and less complicated than Intel’s, Doherty said.
IBM’s chip is “more manufacturable” as it has a simple integrated silicon structure and is cheaper to make, while Intel’s structure needs additional physical components, Doherty said.
Intel however said its optical components are integrated and have testing and cost advantages.
The chips are also fundamentally different in how they transfer data, but have their cost and performance advantages. IBM’s chip transfers data over a single fiber using four different “colors” as channels, while Intel’s technology could scale faster with more fibers added to optical cables, Doherty said.
Intel has built MXC optical cables that can have up to 64 fibers, with each fiber transferring data at 25Gbps. But adding fibers can be expensive, and IBM’s single-fiber implementations could be cheaper and meet many speed and distance requirements in data centers, Doherty said.
IBM declined to comment on when the silicon photonics chips would reach the market.