Can the grid-computing craze accommodate a new optical switching and routing startup? Chiaro Networks thinks so.

Chiaro this week said it has shipped a working optical "router" to be used in the OptIPuter, a five-year, $13.5 million grid computing project funded by the National Science Foundation (See Watch for the Grid). The OptIPuter, a joint venture of the University of California at San Diego and the University of Illinois at Chicago, is a network of several computing systems that are linked by optical fiber.

Grid computing systems such as OptIPuter allow their resources to be shared by all the network's end users. If you think of a grid as one giant computer stretched over a large area, Chiaro's system and the optical fiber connecting to it would be analogous to the bus that links the storage, processing, memory, and other computing elements together in a PC.

Chiaro's initial prototype isn't really a "router" per se, but rather a giant, super-fast optical packet switch. Initially the company hopes to simplify service-provider networks by introducing a core optical system that's so fast and so scalable that it eliminates much of the need for an aggregation layer between the network's core and its edge.

Chiaro says it has a switching technology, called Optical Phased Array, that helps it switch a large number of ports at nanosecond speeds. "What seemed to be mutually exclusive in the past was both large port counts and ultra-fast switching speeds," says Ken Lewis, Chiaro's CEO. Lewis claims the company's routing platform, called Enstara, is a step beyond today's optical switches, which handle a high number of ports at millisecond speeds, or today's IP routers, which switch a smaller number of ports at nanosecond speeds.

Here's an oversimplification of how the company's optical switch technology works: It takes light from an input fiber and sends it through 128 gallium arsenide waveguides (see Arrayed Waveguide Gratings (AWGs)). As the light travels through the waveguides, a voltage is applied to control or “bend” the light. As the light comes out the other end of the waveguides, the light enters a five-inch air gap, where constructive and destructive interfering patterns occur.

This constructive and destructive interference is akin to dropping two stones in a pool of water and watching each set of ripples. Some of the ripples will combine and make bigger (constructive) ripples while others will (destructively) collide and cancel each other out. [Ed. note: we had to dust off our high school physics books for that one.]

Anyway, the voltage controls the location of the constructive interference, which in turn creates bright spots that allow the light to be steered and aimed at any one of the 64 outputs on the switch module and -- voila! -- the light is switched in nanoseconds by a machine with no moving parts.

Chiaro's 64 x 64 optical switch module was tested by AT&T Research Labs, as noted in a paper published this month at the Lasers & Electro Optics Society (LEOS) annual meeting in Scotland. "We measured the [Chiaro switch module's] transmission performance with the data rate and channel count per fiber scaled to 160 Gbit/s (40 Gbit/s x 4 wavelengths)," wrote the paper's eight authors. "For a fully loaded switch, this capacity would translate into a potential non-blocking switch element throughput of (64 x 160 Gbit/s) or 10.24 Tbit/s."

"Switch operation is based on fast electro-optic effect, and measured switching time was better than 20 nanosecond, sufficient for IP format packet switching," the paper states.

The Chiaro system being installed in the OptIPuter program is running each port at 10 Gbit/s, and it's not equipped with hundreds of ports, Lewis says. But because it switches optically, he claims, the rate and format of the payload don't matter to the optical switching system. In theory, Chiaro's switch can operate at a much higher data rate and can handle four colors of light coming into each port, which would scale the system's overall capacity significantly.

Chiaro is also talking up the technology that protects the system, saying it will allow for hot capacity upgrades and expansions. In lab tests, Chiaro says its system has been able to maintain "state" with hundreds of peers while failing over from one master control processor to another without losing packets or causing a network outage.

Interesting? You bet. Commercially viable? We'll see.

There's a question of how many service provider networks worldwide would actually need, buy, and use a switching platform of the scale Chiaro is hinting at. Call it what you will -- optical router or optical switch -- but neither market is doing well right now, and the core router market is fiercely competitive (see Router Vendors Look for Bottom).

Chiaro has beaten the odds so far, just by being able to get a product in use in such a visible project as the OptIPuter. Optical switch makers such as BrightLink and optical routing vendors such as IP Optical Inc. both had high hopes and interesting technology, but didn't survive quite so long (see Brightlink Works on Its Grooming and BrightLink Is Fading Out).

Chiaro says it has raised $210 million to date and employs 221 people. The company has been granted about 25 patents and has filed for 26 more. The company closed its last round of funding, a Series D round of about $80 million, in February. "With any luck at all, we won't have to raise more money," Lewis says.

— Phil Harvey, Senior Editor, Light Reading
www.lightreading.com