Scientists from Intel Corporation have achieved a major advance using silicon manufacturing processes to create a novel ‘transistor-like’ device that can encode data onto a light beam.
The ability to build a fast photonic (fibre optic) modulator from standard silicon could lead to very low-cost, high-bandwidth fibre optic connections among PCs, servers and other electronic devices.
Intel researchers are said to have split one beam of light into two separate beams as it passed through silicon. They then used a transistor-like device to hit one of the two beams with an electric charge, inducing a ‘phase shift.’
When the two beams of light are re-combined the phase shift induced between the two arms makes the light exiting the chip go on-and-off at over one gigahertz, 50 times faster than previously produced on silicon. This on-and-off pattern of light can be translated into the ones and zeros needed to transmit data.
‘This is a significant step toward building optical devices that move data around inside a computer at the speed of light,’ said Patrick Gelsinger, senior vice president and chief technology officer at Intel. ‘It is the kind of breakthrough that ripples across an industry over time enabling other new devices and applications.
‘It could help make the Internet run faster, build much faster high-performance computers and enable high bandwidth applications like ultra-high-definition displays or vision recognition systems.’
To date the fabrication of commercial optical devices has favoured expensive and exotic materials requiring complex manufacturing, limiting their use to such specialty markets as wide area networks and telecommunications.
Intel’s fabrication of a fast silicon-based optical modulator with performance that exceeds 1GHz is said to demonstrate the viability of standard silicon as a material for bringing the benefits of high-bandwidth optics to a much wider range of computing and communications applications.
Silicon Photonics research at Intel began in the mid-1990s with efforts to test and measure transistors switching inside microprocessors optically. Although silicon appears opaque to the naked eye, it is transparent to infrared light.
‘Just as Superman’s X-ray vision allows him to see through walls, if you had infrared vision you could see through silicon,’ said Mario Paniccia, director of silicon photonics research at Intel.
‘This makes it possible to route infrared light in silicon, which is the same wavelength typically used for optical communications. The way electrical charges move around in a transistor when voltage is applied can be used to change the behaviour of light as it passes through these charges.
‘This led us to explore manipulating the properties of light, such as phase and amplitude, to produce silicon-based optical devices.’
The 1GHz of today’s experimental device equates to a billion bits of information travelling down a single fibre. Intel researchers think they can scale the technology up to 10GHz or faster in the future. A single photonic link can carry multiple, simultaneous data channels at the same speed by using different colours of light. Additionally, fibre-optic cables are immune to electro-magnetic interference and cross-talk, which makes traditional high-speed copper interconnects difficult to build.
‘We have a long-term research program in place to explore how we can apply our silicon expertise in other areas with a long-term goal of developing integrated optical devices,’ Paniccia said.