MEMS -> D-MEMS yield new flexibility for optical nets

D-MEMS yield new flexibility for optical nets
By Matthew Heydinger, Senior Product Manager, Lightconnect Inc., Newark, Calif., m.heydinger@lightconnect.com, Asif A. Godil, Chairman, Chief Technology Officer, Lightconnect Inc., Newark, Calif., EE Times
July 12, 2001 (7:09 p.m. EST)
URL: http://www.eetimes.com/story/OEG20010712S0073

Until recently, fiber networks were primarily static, point-to-point links with most of the intelligence, provisioning and grooming functions provided by electronics at the ends of each link. As network architectures grow in size and complexity, however, this approach to building and maintaining network infrastructure does not satisfy the requirements of reliability, efficiency and cost effectiveness demanded by service providers.

When the ribbon array is displaced by a quarter wavelength, the light reflected from th e two surfaces is completely out of phase and destructive interference occurs for the nominally reflecting beam. At this point, all of the light is totally diffracted and none is reflected.

D-MEMS actuators are manufactured using standard CMOS processes and materials that take full advantage of established semiconductor foundries with state-of-the-art equipment. This provides manufacturing flexibility and allows for multiple sourcing.

Devices based on D-MEMS have inherent advantages in speed, reliability and power consumption. Since the ribbon array only needs to deflect a few tenths of a micron, the structure can be made very stiff. This stiffness, coupled with low mass, results in a high resonant frequency. This leads to fast response times, typically tens of microseconds.

Noise immunity
An important added advantage of this is immunity to ambient acoustic noise and vibration. Fabricated devices are very reliable since, with these small deflections, the material experie nces negligible fatigue. Devices have been actuated more than 10 billion times with no measurable change in performance.

The D-MEMS grating is effectively a small capacitor in an electrical circuit that has very low power dissipation. Consequently, the device consumes little energy, and does not need to dissipate excess power. This is in contrast to devices using thermal or magnetic actuation mechanisms, which consume considerably more power and may require thermal management.

Lightconnect is currently developing a family of dynamic optical components based on D-MEMS technology. The components demonstrate world-class optical performance and manufacturability and include variable optical attenuators, dynamic gain equalizers, channel equalizers, programmable add/drop multiplexers and high-speed switches. One example is the fast variable optical attenuator (FVOA).