Page 158 - Optical Switching And Networking Handbook

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Optical Switching Systems and Technologies 143

cables. Advances in fibers, lasers, and photo detectors have enabled
the introduction of telecom standards with data rates higher than 10
Gbps.The adoption of DWDM permits many independent data chan-
nels carried on different optical wavelengths to coexist on one fiber.
This has further increased available network bandwidth. Mean-
while, an increase in the variety and volume of data traffic passing
through these fiber links brings new challenges as service providers
manage and expand their networks.

Economical MEMS

Often with integrated microactuators built into them, these MEMS
devices typically are addressed using electrical signals to produce
controlled motion of the micromechanical structures on the chip.The
batch-processed nature of the fabrication procedure means that
MEMS devices can be mass produced on a large scale, which reduces
manufacturing costs. In addition, the extremely small physical size
and mass of these silicon “machine parts” often make them more
robust and capable of faster operation than conventional macro-
scopic mechanical devices.
Onix Microsystems is bringing optical MEMS to the market with
a range of optical switching products based on patented micromirror
technologies. The key element of its switching engines is a two-
dimensional matrix of micromachined mirrors fabricated in single-
crystal silicon. Control signals applied to the MEMS chip fix the
position of each individual mirror to either pass or intersect the
input light beams, directing each incoming light signal to the desired
output port.
Because the intersecting micromirrors must direct the outgoing
light beams into small-diameter fiber cores (typically fewer than 9
microns), tight control of the mirror angles is vital to minimizing
power loss incurred from passing through the switch. Extremely low
insertion loss and channel cross-talk are achieved by this architec-
ture to produce compact, all-optical switch modules with up to 64
input-output ports. The concept is that as the light is reflected off
mirrors in the switching system, the micromirror is sent a signal to
move in a certain direction.As the mirror moves, the light is bounced