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Calient Claims Breakthroughs On Optical Switches

Startup sets new standard for density, combines all-optical core with network intelligence

May 22, 2000

3 Min Read
Calient Claims Breakthroughs On Optical Switches

Calient Networks, Inc. http://www.calient.net today announced a couple of optical switch developments that appear to be significant breakthroughs.

First, Calient says that it can build all-optical switches that are an order of magnitude denser than previously possible. The startup, which has been in stealth mode until now, says that it can pack a complete 1,000 by 1,000 port optical switch into a box the size of a kitchen drawer.

An equivalent size all-optical switch demonstrated by Xros Inc. http://www.xros.com earlier this year occupied two and half 7-ft racks (see Xros Launches First 1000-Port All Optical Cross Connect). “We’re building something 20 times smaller,” says Charles Corbalis, Calient’s president and CEO.

Second, Calient is developing software that will enable its switches to automatically set up and tear down strings of wavelengths across a backbone, in response to signaling from edge equipment such as routers.

Other vendors – notably Ciena Corp. http://www.ciena.com (via its acquisition of Lightera), Cisco Systems Inc. http://www.cisco.com (via its acquisition of Monterey), Sycamore Networks Inc. http://www.sycamorenet and Tellium, Inc. http://www.tellium.com - are developing similar software. But their switches have electrical rather than all-optical cores.

Achieving a big improvement in optical switch density at the same time as adding network intelligence is a big deal. It promises to slash costs in carrier networks, make future upgrades easier, and enable operators to respond much faster to customer requirements.

Packing optical switching capacity into a much smaller space delivers three big benefits, according to Tim Dixon, Calient’s VP of marketing. First, Calient’s switch will be able to scale to “many thousands of ports.” Second, light has to travel much shorter distances within the switch core, which means losses are lower. “The target is 6.5 decibels,” says Corbalis. Third, the switch will be less susceptible to instability caused by temperature changes and vibration, he adds.

All of this is achieved by using an order of magnitude smaller MEMS (micro-electro-mechanical systems) compared to previous developments. Calient uses arrays of tiny tilting mirrors to bounce the light from input to output port, in much the same way as Xros. However, its mirrors are much smaller. A whole array of Calient’s mirrors is about the same size as a single mirror in the Xros switch, according to Corbalis. Switching fabric the size of a sugar cube could handle 100 wavelengths, he adds.

Calient won’t say how it’s achieved this breakthrough, apart from noting that its got a couple of renowned optical experts on staff – John Bowers and Noel MacDonald – and that it has close links with the photonics lab at the University of California Santa Barbara. It's using "a couple of independent foundries" to manufacture the MEMS to its design.

Calient’s other claim to fame – software that delivers network intelligence – is equally impressive. Once again, it’s got experts on staff that lend weight to its claims. “I’ve done it before,” says Corbalis, who was co-founder and VP of engineering at Stratacom, whose equipment fueled the roll-out of frame relay services around the world. John Drake developed signaling at Fore Systems before joining Calient as chief network architect. He recently co-authored an IETF draft RFC on Multi-Protocol Lambda Switching (see Calient Networks, Inc).

Having the right people on staff is one thing, of course, and delivering on promises is another. At present, it’s early days for Calient. It’s already developed a 16 by 16 port prototype and is hoping to have a 256 by 256 version ready for display at the Supercomm trade show in a couple of weeks’ time. If that doesn’t seem particularly big, remember that vendors have over-hyped their all-optical switch achievements in the past ( see Xros's OFC Splash Was All Wet and Optical Illusions).

Calient has raised a total of $56 million for its developments. The first round of $6 million came from Enterprise Partners http://www/ent.com, Telesoft Partners http://www.telesoftvc.com and Storm Ventures (a small group of Bay area entrepreneurs). New investors in the $50 million second round, announced today, include Juniper Networks, Inc. http://www.juniper.com (JNPR), Tellabs http://www.tellabs.com (TLAB) and Greylock http://www.greylock.com.

-- by Peter Heywood, international editor, Light Reading http://www.lightreading.com

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