Addressing atmospheric turbulence in optical communications

Researchers from Western Australia’s International Centre for Radio Astronomy Research (ICRAR) have found a way to avoid the need to use radio transmitters in critical communications, using new technology featuring super-fast optical lasers. Their findings, which have been two years in the making, have been published in the journal Scientific Reports.

Although optical communications have been in use since the 1980s, government and industry have continued to rely on >100-year-old radio transmission technology in settings such as satellite communications due to atmospheric turbulence, which causes laser beams to drift away from their intended target. The team’s discovery addresses this turbulence issue by using a very fast steering mirror that can correct for turbulence at a rate of hundreds of times per second. This means that optical wireless transmission can be used in more settings, reducing the need for reliance on slower radio transmission.

Lead researcher Dr Shane Walsh explained that his team found a way to use optical communications to fix upon a rapidly moving target (in this case a drone) in a turbulent environment, with an uninterrupted, high-speed signal. As a next step, the researchers plan to test the technology with a higher altitude aircraft and ultimately a spacecraft in low Earth orbit.

“This is a culmination of more than two years of research and testing, and takes ground-to-space communications from what was effectively a ‘dial-up’ speed in turbulence to a super-fast ‘broadband’ speed,” Walsh said.

Researchers are now developing a purpose-built, optical communications ground station in WA which, when complete, will allow them to further develop and commercialise the technology. It is expected to be used by industry and governments alike, in applications as diverse as communications with spacecraft, meteorology, defence and disaster management

Image caption: Schematic of the team’s deployable optical terminal and experiment. Image courtesy of the study authors under CC BY 4.0.