As data travels around the internet, it's routinely switched from electrical signals to light in order to travel through the network's fiber optic backbone. To do this, the signal travels through devices called electro-optic modulators. However, these devices are really bulky (usually several centimeters across) and require an inordinate amount of power to operate. However, a team from ETH Zurich recently published research in the journal Nature Photonics that outlines how they built a modulator one hundred times smaller and less power hungry than conventional models.
The team, led by professor of photonics and communications Juerg Leuthold, built the device out of a 150 nm layer of gold seated atop an organic material that changes its refractive index when electricity is applied. They were able make the modulator smaller than the industry standard light wavelength of 1.5 micrometers by first changing the light into surface-plasmon-polaritons. This involves converting the light into an electrical field and electrons which travel along a metal strip. At the end of the strip they convert back into light. It's roughly akin to folding up a cardboard moving box, slipping it under a door, then unfolding it.
"It's incredibly small and simple, and on top of that it's also the cheapest modulator ever built", Leuthold explains. And using just a few thousandths of a watt to convert 70 Gbs of data per second, it draws one hundredth the power as today's models. The ETH Zurich team is currently performing long-term performance testing on the new device. There's no word on when it will be commercially viable.