However, a team of physicists from the UK, Germany, New Zealand and Canada believes that optical angular momentum (OAM) could help to overcome current difficulties with using twisted light across open spaces.
The researchers examined the effects on the phase and intensity of OAM carrying light over a real link in an urban environment to assess the viability of these modes of quantum information transfer. The tests, over a 1.6km free space link in Erlangen, saw data passing over fields and streets and close to high-rise buildings simulating an urban environment and the atmospheric turbulence that can disrupt information transfer in space.
While previous studies showed that OAM communication was feasible, the effects of turbulent air on the phase of the structured light propagating over links of this length had not been considered.
The team’s findings are said to highlight the challenges – not previously observed – in developing free space optics as a replacement for fibre optics.
Dr Martin Lavery, head of the Structured Photonics Research Group at University of Glasgow, said: “In an age where our global data consumption is growing at an exponential rate, there is mounting pressure to discover new methods of information carrying that can keep up with the huge uptake in data across the world.
“Free space optics is a solution that can, potentially, give us the bandwidth of fibre, but without the requirement for physical cabling.
“We are getting ever closer to developing OAM communications that can be deployed in a real urban setting.”