After years of developmental obscurity, the spotlight is now shining on optical switching. Following the debut of Lucent Technologies Inc.'s (www.lucent.com) WaveStar early this year, rainbows of new optical switch products and initiatives have been announced by leading vendors.
For instance, announcements have come from industry vets such as Siemens AG's Information and Communication Networks (www.icn.siemens.com), Agilent Technologies Inc. (www.agilent.com) and the Optics division at Alcatel Inc. (www.alcatel.com). Startups, such as Optical Micro-Machines Inc. (www.omminc.com) and Xros Inc. (www.xros.com), are also in the mix.
Acquisitions are heating up as well. Almost as soon as it surfaced as a provider of technology for optical switching, Xros was snapped up by Nortel Networks Corp. (www.nortelnetworks.com) on March 14 for a jaw-dropping $3.25 billion--an astounding sum to pay for a company that had yet to earn any revenue.
As the activity heats up, so does the speculation about which technology is really positioned to win and if, in fact, any of the current generation will prove to be the winning solution for the long term.
All-optical switching has attained Holy Grail status among some service providers, particularly large network operators, such as AT&T Corp. (www.att.com) and MCI WorldCom Inc. (www.wcom.com). These companies are seeking a more efficient way to switch wavelengths. Today they use large cross-connects from providers such as Ciena Corp. (www.ciena.com), Sycamore Networks Inc. (www.sycamorenet.com) and Tellium Inc. (www.tellium.com) that convert signals from optical to electricity and back again to optical (OEO conversion).
These cross-connects work well for wavelengths carrying up to 10gbps. However, "in our interviews with carriers," says Lawrence Gasman, president of Communications Industry Researchers Inc. (www.cir-inc.com), "there really is a need for a moderately large optical cross-connect that can handle 40gbps and above--if someone can build one that works."
Two technologies have emerged so far as the prime contenders to produce working products in the next year: micromirror (MEMS) technology and Agilent's bubble technology.
MEMS, which is the basic approach used by Xros, employs microscopic mirrors embedded in a silicon substrate to provide an optical cross-connect. The mirrors are steered electronically to reflect laser beams in different directions. The strength of the Xros approach is said to be its use of larger mirrors, which means it is easier to focus the light beams.
A key issue in MEMS technology is the size of the cross-connect. Xros claims to have a 1,100 by 1,100 matrix, while the technology so far demonstrated by OMM is a 32 by 32 matrix on a chip. The OMM chips, however, can be combined to make larger matrices, such as a more-desirable 512 by 512 matrix. Gasman adds that carriers say all-optical cross-connects will not save much money unless they can reach 1,000 ports or more.
Agilent uses technology from its inkjet printing technologies to steer wavelengths. The basic chip is a matrix of 32 by 32 "waveguides," which are simply grooves in glass, filled with a liquid that allows light to pass easily. At each intersection of the waveguides, a bubble can be inserted. If the bubble is there, the wave cannot continue down the groove and is reflected off to one side or the other, switching the wavelengths.
"Nobody at this point is really offering a perfect answer to optical switching," Gasman says. "Necessity is the mother of invention. Here are service providers saying 'We want these things,' and this is a real encouragement to companies and investors to try to make it work."
The Agilent technology is very rugged, says David Andersen, research and development manager at Agilent Optical Networking. "It is permanently aligned on a piece of glass, and there is no drift or change in performance. It is immune to vibration--a very simple technology."
Alcatel has announced that it will use Agilent's technology for an optical switch.
