Nanoscale photonic silicon technology

Last December 6, IBM's Silicon Research Group published an important result in the application of Silicon-based photonic photonics, using light to replace copper fibers for the transmission of information in the " brain "of a chip.

This success is an important turning point in the creation of supercomputers - a long-standing dream, when current chips are still limited by the problem of heat dissipation, energy consumption and large size - instead, a single chip, used for personal computers, works faster, cooler and consumes less energy.

Turn supercomputer dreams on one chip into reality

The results are published in the journal Optics Express , which IBM researchers emphasize is an extremely important success in transmitting information between cores, or a " brain " of a chip, using Using light pulses, replacing electrical signals in ordinary conductors, to create a supercomputer on a completely silicon chip.

Figure 1: Principle of operation of optical modulator (IBM)

IBM's optical modulator functions to convert a digital electrical signal on a conductor into a series of light pulses, to circulate and process in a silicon-based photonic wave path. First, a source laser (red) shines on the optical modulator. Optical modulator (black box with IBM brand) is actually a very fast " shutter " to control the laser signal, or block the source signal, or let it pass through the output wave path. When a digital electrical signal is pulsed (digitally encoded "1", yellow) coming from the left of the controller, a short pulse of light is allowed to pass to the right optical output set. Conversely, if there is no electrical pulse at the controller (encoded by the "0" number), this regulator will prevent the light from reaching the output. With this treatment, the device " adjusts " the intensity of the input laser, and turns digital electrical signals (1 and 0) into light pulses.

The modulator used by the researchers is the electromechanical Mach-Zehnder, silicon-based, to convert the electrical signal to a pulse signal . It is worth noting that this modulator is less than 100 (and is capable of collecting up to 1,000 times smaller) than current modulation devices. This is also the last device in an integrated siliconized system, to build a chip entirely on silicon. Silicon technology is still a good candidate, compared to technologies using other materials such as Germanium, or Gallium Arsenide, Cadmium Sulfide and Gallium Nitride.

Abundance (silicon is one of the most abundant elements on earth), and research investments throughout 30 are the strengths that silicon has. The research team used silicon platform regulators that were not outside of this goal, and it was a cause of cost reduction, an important issue and a decision when commercializing products; Combined with a fully optical processor, it will consume less energy, be more secure, and increase the capacity of information transmission between cores up to hundreds of times more than the current wiring method.

Figure 2: Internal structure of optical modulator (IBM)

IBM's optical modulator uses silicon-based photonic waveguides to control the light source on a silicon chip. Digital electrical signals are transmitted into silicon nanophotonics waveguides created by p + -i-n + semiconductors via electrodes (gold). Charges (holes - blue particles, and electrons - red particles) enter the path and change the optical properties of silicon; It is also the mechanism of optical regulators.

"The work is still being done by the IBM team and a number of industrial organizations to incorporate and finalize the cores on a chip, which compares to the current heat problem in comparison with current chips. As the problem of dealing with growing volumes of information, " Dr. TCChen, deputy director of IBM's Science and Technology Department, said: " We have taken an important step towards making the sets. link between chip-sized cores in minimal size and efficient capacity, in a direction that no other group has ever done. "

One of IBM's most powerful chips, the Cell processor, is used in the Sony Playstation 3 game, containing 9 cores in a chip. This new technology will aim at an efficient - power method that can link hundreds to thousands of cores together in a small chip, and replace the reimbursement of wires. Using light instead of wires to transmit information between cores will increase the speed by up to 100 times, while consuming only one tenth of the energy compared to current wiring technology.

Figure 3: Simulation of path operation
wave in optical modulator (IBM)

Waveguide is made up of silicon fibers (purple) with a length of 200 times smaller than our hair, on a silicon insulating membrane (SOI). Light is completely confined to silicon nanoparticles, as shown in the figure, are concentric colored ellipses. This strong light confinement makes the optical modulator significantly reduced in size compared to current technology.

Figure 4: Model proposed silicon chip using complete optical path

This is the proposed model to implement a fully optical path with N channels, each channel can transmit 10Gps of information. The first N channels are demultiplexed by wavelength division method in WDM photonic circuit, then sorted and reversed through OXC optical regulator, and channeled back by wavelength multiplexer. Data sources can be buffered in an optical slowing path if necessary. Channels are controlled together with integrated Ge sensor. CMOS logic circuits will perform information processing. Electric pins connect photovoltaic chips to other chips via electrical signals.

" We believe this is an important step forward in the field of silicon-based nanoparticles ," said Dr Will Green, the project's lead researcher. "Just like fiber optic networks have helped to develop and expand the internet by enabling users to exchange a huge amount of information from everywhere on the earth, their technology. IBM will also bring similar capabilities on computer chips. "

Details at IBM.com

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