LIGHT Unto the Nations
Bright solutions for optical computer communications win
a TAU-initiated consortium Israel’s first European Union research grant
Computer chips consist of millions of switching elements (“gates”) that can
pass, stop or change an incoming electrical signal. But while these switches
have become smaller and faster, electronic connectivity has lagged far behind.
The time needed for an electrical signal to simply traverse the network has
become a limiting factor in computer communications speed.
That is until now. A new TAU approach for intra-chip connectivity based on
optical technology promises a revolution in communications speed and
reliability.
Named Reconfigurable Optical Devices for Chip Interconnects (RODCI), the
TAU research project was the first in Israel to win full funding by the
European Union Research and Development Program (ESPRIT) since Israel
became an Associate Member of the EU. Altogether ESPRIT has allocated
$3.5 million for the $5 million project, with funds being disbursed among
TAU’s academic and industrial partners in RODCI.
Optical vs. electrical computing
Light signals can travel much faster than electrical ones and represent the
ultimate in signal speed (light travels 30 billion cm a second.). But there
remained the question of how to design switches that could make light signals
perform the same tricks as their electrical counterparts.
Previous solutions were cumbersome at best. In one hybrid electrical/optical
system, light signals hit a photocell which converted them into electrical
currents. These were amplified and electrically switched. Finally, the current
was converted back into light via a diode laser and the signal moved on.
By contrast, the TAU team’s solution was simple and efficient. They
successfully created a series of all-optical switches which can perform even
complicated switching tasks. Based on the polarization properties of light, the
switches are highly “dynamic,” allowing greater flexibility in the routing or
rerouting of signals (i.e. reconfigurability).
Aside from being quicker, an optical solution to connectivity also solves
severe problems of power dissipation in electronic circuits and reduces
electromagnetic interference and cross-talk.
The TAU approach was mainly based on the master’s thesis project of Dan
Marom, conducted under the supervision of Dr. David Mendlovic of the
Laboratory of Optical Image and Signal Processing, the Department of
Electrical Engineering--Physical Electronics at the Fleischman Faculty of
Engineering. The adaptation of this work for the requirements of chip
interconnection was done jointly by Dr. Mendlovic and Prof. Emanuel Marom,
Dean of Research and Development at TAU.
International consortium
Although the present prototypes work and have been patented, there exists
considerable room for optimization. TAU joined forces with a large
consortium of R&D and industrial partners to develop all-optical networks for
major applications.
TAU’s Israeli partner in the RODCI venture is the Rehovot-based company
EL-OP -- experts in the sphere of optical elements miniaturization and system
integration. Main partners on the European end are Thomson CSF-LCR
(France); and the French Optical Institute of the University of Paris-South.
A new family of all-optical switches developed by
TAU laser scientists can rapidly transform an array of four incoming light signals into any
of (up to) 24 different output configurations. |
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