IBM researchers say they have created the fastest nanophotonic avalanche photodetector, a key element in the development of technology to use pulses of light rather than traditional copper wires for chip-to-chip communication. Researchers say silicon photonics technology will lead to faster, more energy-efficient computing.
IBM researchers have taken their latest
steps in their efforts to enable chips to communicate via pulses of light
rather than copper wires, a transition that could boost the performance and
speed of computers while greatly improving energy efficiency.
IBM officials March 3
announced an advancement in the development of a nanophotonic avalanche
photodetector. The device, which takes light and converts it into electricity,
is the fastest of its kind, according to IBM
researchers, receiving optical information signals at 40G bps and multiplying
them by 10.
It also consumes less power than similar devices, running on a
1.5V voltage supply, which IBM says is 20
times smaller than what they've demonstrated in the past.
"This invention brings the vision of on-chip optical
interconnections much closer to reality," T.C. Chen, vice president of science
and technology at IBM Research, said in a
statement. "With optical communications embedded into the processor chips, the
prospect of building power-efficient computer systems with performance at the
exaflop level might not be a very distant future."
IBM researchers are
publishing their findings in the latest issue of Nature magazine. A video of IBM's
be seen here
IBM, Intel and others are
looking to develop on-chip components that use light to transmit data rather
than the copper wiring found in traditional electrical interconnects. Industry
observers say that given the speed and energy efficiency improvements promised
by the technology, the development of optical communication devices will be a
key to the way computers are built and operated over the next decade.
With major chip vendors such as Intel, Advanced Micro Devices
and IBM-and even newer processor makers, such
-rapidly adding a greater number of processing cores onto a CPU,
the need to improve the speed of data moving between the chips in a system, or
between the servers themselves, is increasing.
Telecommunication companies already are replacing traditional
telephone lines with fiber optic cables. The goal now is to shrink that
capability so that the photonics can be used at the microprocessor level.
That is why other tech vendors also are working to develop
optical communication devices for computer chips. Intel has been developing
such technology for about seven years, and in December 2008 unveiled
its own avalanche photodetector device
Other companies, such as Luxtera, also are working on such
technology. In August 2007, Luxtera rolled out Blazar, a 40GB optical cable for
use in HPC (high-performance computing)
A key in the efforts of both IBM
and Intel is the use of silicon and germanium in creating the avalanche
photodetector devices. Both silicon and germanium are currently used in
developing current processors, which will make it easier and cheaper to
develop, rather than using other kinds of materials to build the components.
The devices also are made with standard chip-manufacturing processes, according
The avalanche photodetector works in a way described by its
name, according to IBM. Like an avalanche on
the slope of a mountain, a light pulse at first frees up a few charge carriers,
which then frees up other charge carriers, creating an avalanche effect until
the original signaled is amplified many times over.
The IBM device does this
faster than that of others, taking place within a few tens of nanometers.
"This dramatic improvement in performance is the result of manipulating
the optical and electrical properties at the scale of just a few tens of atoms
to achieve performance well beyond accepted boundaries," Solomon Assefa, a
research staff member for IBM Research and
the lead author on the paper, said in a statement. "These tiny devices are
capable of detecting very weak pulses of light and amplifying them with
unprecedented bandwidth and minimal addition of unwanted noise."
IBM's announcement is the
latest in a series made in the vendor's building of what researchers are
calling the "nanophotonics toolbox" of devices.
In 2006, IBM Research
unveiled a silicon nanophotonic delay line, and a year later announced the
development of a very compact silicon electro-optic modulator, for converting
electrical signals into pulses of light.
In March 2008, IBM announced
what researchers said was the world's smallest nanophotonic switch for
directing traffic in on-chip optical communications.