A depiction of noise in a signal in an electromagnetic field. Moscow Institute of Physics and Technology

Of the various possibilities created by nanotechnology, some of the obvious ones are in the field of computers and processors. A research paper published recently put forward a theory to establish the limits of data transfer rates in optoelectronic microprocessors and ways to reduce noise in the electromagnetic field.

Published in the journal Physical Review Applied under the title “Spontaneous Emission and Fundamental Limitations on the Signal-to-Noise Ratio in Deep-Subwavelength Plasmonic Waveguide Structures with Gain,” the paper proposes a way to evaluate the maximum possible data transfer speeds in nanophotonic processors by understanding the fundamental limitations imposed by noise in electromagnetic fields.

In their study, authors Andrey A. Vyshnevyy and Dmitry Yu. Fedyanin from the Moscow Institute of Physics and Technology consider nanophotonic components, which are up to four orders of magnitude faster at data transfer than their nanoelectronic counterparts. These nanophotonic components use surface plasmons, which can be thought of as compressed photons. These plasmons, which would otherwise lose signal strength, can travel long distances only along what are called plasmon waveguides between the transmitter and the receiver. However, while these waveguides amplify signal strength, they also increase the amount of associated noise.

“Noise plays a key role in nearly half of all the devices in our homes: from cell phones and television sets to the fiber-optic channels that are the backbone of the high-speed internet. Signal amplification inevitably decreases the signal-to-noise ratio. In fact, the more gain an amplifier provides, or, in our case, the greater the signal loss it needs to compensate, the higher the level of noise it produces. This problem is especially pronounced in plasmonic waveguides with gain,” Fedyanin said in a statement sent to International Business Times.

The researchers suggest using their theory could enable data transfer speeds to exceed 10 Gbps per data communication channel using specific wavelengths of light. Using a copper wire of similar physical dimensions as the optoelectronic circuit would allow speeds of only up to 20 Mbps, about 500 times slower.

The study demonstrates “that by using both optical and electrical filtering techniques, it is possible to decrease the noise to a level sufficient for practical applications at telecom and mid-infrared wavelengths.”