IBM scientists have created a tiny device that could lead to the eventual use of photons to replace electrons for component connection.
Scientists have slowed light down to less than one-three-hundredth its usual speed by directing it down a channel of perforated silicon photonic crystal waveguide.
The device allows the light’s speed to be varied over a wide range by applying an electrical voltage to the waveguide, IBM explained.
The company noted that its researchers have known for some years how to slow light under laboratory conditions, but doing it on a silicon chip using standard silicon with standard micro- and nanoelectronic fabrication technology, is claimed to be a first.
The device’s small size, use of standard semiconductor materials and ability to more closely control this “slow light” could make the technology useful for building ultra-compact optical communications circuits that are practical for integration into computer systems.
Using a photonic crystal waveguide - a thin slab of silicon punctuated by regular arrays of holes that scatter light, the IBM team has slowed light.
The pattern and size of the holes gives the material a very high refractive index - the higher the refractive index, the slower the light.
Heating the waveguide locally with a small electrical current alters the refractive index, allowing the speed of light to be quickly tuned over a large range with very low applied electric power.
The manufacturing processes used to build the device are available in nearly any semiconductor factory and could be applied to create a variety of nanophotonic components such as optical delay lines, optical buffers, and even optical memory.
All of these components would be useful in building computer systems knitted together by powerful optical communications networks, the company concluded.