Contents:
Increasing demand
for optical network bandwidth
The
development of our information based society is characterized
by an enormous growth in bandwidth demand. Usually, two types
of traffic on an optical network are specified:
- Voice traffic
- Data traffic
Over the last few years, the
internet (data traffic) has grown so much that it now
exceeds telephony (voice) traffic. Also, such new
applications as distance-teaching and conferencing over the
internet and tele-working (working from home) are driving a
huge increase in bandwidth requirements. Furthermore, the mere
growth rate in the number of internet users help fuel this
increase. This puts great demands on the development of
internet technology that can provide this extra capacity.
It is especially in the so-called trunk network,
or backbone network, that more capacity is required in order
to support the demand increase. But as applications develop,
faster connections between the trunk network and individual
users will be required in order to support such applications.
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Supporting the increasing
demand
The basic medium in optical
communication networks is the optical fiber. So far, the
optical fiber is not the limiting factor in providing
bandwidth.
The problem lies in the components that combine traffic
from single users onto the backbone. Such components have to
be very complex to support the high bitrates and various bit
formats supported in normal communication networks today. So
far, the processing at the backbone rates (so far up to 10
Gbit/s) have been electronic. However, as networks develop to
higher bitrates and more wavelengths on a fiber, all-optical
solutions are sought which handle this development much more
gracefully.
One way of increasing transmission capacity is to simply
add more wavelength channels. This method is called
Wavelength Division Multiplexing (WDM)
because it uses the wavelength regime to separate various
channels. The other way is called Time Division
Multiplexing (TDM) because various channels are
distinguished by their position in time. The WDM technique is
by far the commercially most developed method of increasing
transmission rates. However, the two methods are not mutually
exclusive. Actually, one can increase transmission rates by
increasing speed by, at the same time, increasing the number
of wavelengths (WDM) and the basic rate (TDM) of each channel.
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 SCOOP:
Semiconductor
COmponents for Optical signal Processing
The
SCOOP project is
concerned with TDM, or more precisely OTDM (Optical TDM),
systems. We design, develop, and fabricate semiconductor
devices for optical signal processing. The work is concerned
with increasing operation speeds of components used for
optical signal processing, i.e. short-pulse generators,
add-drop multiplexers, wavelength converters, and signal
regenerators.
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