US researchers have demonstrated a laser designed to generate high-speed
pulses of light on silicon that can speed data transmission.
The
Optical
Society of America reported today that scientists have built what is thought
to be the world's first mode-locked silicon evanescent laser.
The device can deliver stable short pulses of laser light that are useful for
optical applications, including high-speed data transmission, multiple
wavelength generation, remote sensing and highly accurate optical clocks.
"This new work is a significant step towards the goal of combining lasers and
other key optical components on silicon, providing a way to integrate optical
and electronic functions on a single chip and enabling new types of integrated
circuits," said the Optical Society report.
"It introduces a more practical technology with lower cost, lower power
consumption and more compact devices."
The Society noted that present-day computer technology depends on weak
electrical currents for data communication within the silicon-based
microprocessor.
By causing silicon to emit light and exhibit other potentially useful optical
properties, the integration of photonic devices on silicon becomes possible. The
problem in the past was that it was nearly impossible to create a laser in
silicon.
However, a research team led by John Bowers at the
University
of California, Santa Barbara and
Intel
successfully created laser light from electrical current on silicon by placing a
layer of indium phosphide above the silicon.
The scientists used electrically-pumped lasers emitting 40 billion pulses of
light per second built on a hybrid silicon platform developed last year.
"This is the first-ever achievement of such a rate in silicon and one that
matches the rates produced by other media in standard use today," said the
researchers.
"These short pulses are composed of many evenly spaced colours of laser
light, which could be separated and each used to transmit different high-speed
information, replacing the need for hundreds of lasers with just one.
"Creating optical components in silicon will lead to optoelectronic devices
that can increase the amount and speed of data transmission in computer chips
while using existing silicon technology."
Employing existing silicon technology is a desirable goal because it would
represent a potentially less expensive and easier-to-implement way of
mass-producing future-generation devices that use electrons and photons to
process information.
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