HP Labs researchers have demonstrated a way to use lasers to replace a lot of the electronics that connect servers to racks in data centers, a development that could one day make commercial computers much more power efficient, faster and cheaper.
The so-called photonic interconnect systems (shown right) could replace the backplanes in servers (below), which connect a single server to a rack and the rest of a data center. The interconnect system replaces the electrical system in the rack with an optical bus, akin to the fiber optic systems that carry the bulk of Internet traffic across the country. Lasers send pulses of data through the “multidrop optical bus,” and the various components in the system route the data properly within the data center.
Using lasers to deliver data over glass fibers known as fiber optic cables has been possible for a long time. But its usefulness has been limited by huge components costs. Companies like Intel are trying to convert those components into silicon chips, but so far have had modest success. HP says the photonic interconnect isn’t that expensive to make. The researchers drill holes the size of human hairs in plastic parts that serve as wave guides, or paths to direct the paths of the laser light. Photonic interconnect can transfer data at 10 gigabits a second now and might be able to do 100 gigabits a second. That’s far faster than copper wiring. The signals shown in the oscilloscope below show that the interconnect works.
HP researcher Michael Tan showed off a thin piece of plastic that was created to form a mirror for reflecting light at angles. The plastic strip can route data through a fiber-based system that is compact and can replace the entire backplane of a server. The backplane is the part of the server that networks the server with other computers and hardware in the data center. It can be a bulky part of a server blade, generating a lot of heat on its own. The server blades plug into racks and are used by the thousands in data centers that provide the backbone of a company’s web-based operations.
By removing that conventional backplane and replacing it with something much smaller, the blades generate a lot less heat and can be made smaller. That makes the blades more energy efficient. You can also pack more of them together, allowing a data center to generate a lot more computing power in the same amount of space.
There’s still a lot of work to finish. Tan estimates that the technology could be a commercial product within three years. A sample of the plastic wave guide is shown below.