'Twisted' light for fibre boost
A new development could vastly increase the speed of fibre-optic communication.
Broadband fibre-optics carry information on pulses of light, at the speed of light, through optical fibres. Data speeds are affected by the way the light is encoded at one end and processed at the other.
A new nanophotonic device developed at RMIT can encode more data and process it much faster than conventional fibre optics by using a special form of ‘twisted’ light.
“Present-day optical communications are heading towards a 'capacity crunch' as they fail to keep up with the ever-increasing demands of Big Data,” says Dr Haoran Ren from RMIT’s School of Science.
“What we’ve managed to do is accurately transmit data via light at its highest capacity in a way that will allow us to massively increase our bandwidth.”
Even the current state-of-the-art in fibre-optic communications can use only a fraction of light’s actual capacity to carry data.
This new technology carries data on light waves that have been twisted into a spiral to increase their capacity. This is known as light in a state of orbital angular momentum, or OAM.
In 2016, the same group from RMIT’s Laboratory of Artificial-Intelligence Nanophotonics (LAIN), described for the first time that they had managed to decode a small range of this twisted light on a nanophotonic chip.
However, technology to detect a wide range of OAM light for optical communications has not been viable, until now.
“Our miniature OAM nano-electronic detector is designed to separate different OAM light states in a continuous order and to decode the information carried by twisted light,” Dr Ren said.
“To do this previously would require a machine the size of a table, which is completely impractical for telecommunications. By using ultrathin topological nanosheets measuring a fraction of a millimetre, our invention does this job better and fits on the end of an optical fibre.”
The materials used for the device are compatible with silicon products used in most technology, making it easy to scale up for industry applications.
“Our OAM nano-electronic detector is like an ‘eye’ that can ‘see’ information carried by twisted light and decode it to be understood by electronics. This technology’s high performance, low cost and tiny size makes it a viable application for the next generation of broadband optical communications,” RMIT’s Professor Min Gu said.
“It fits the scale of existing fibre technology and could be applied to increase the bandwidth, or potentially the processing speed, of that fibre by over 100 times within the next couple of years. This easy scalability and the massive impact it will have on telecommunications is what’s so exciting.”
Prof Gu said the detector can also be used to receive quantum information sent via twisting light, meaning it could have applications in a whole range of cutting-edge quantum communications and quantum computing research.
“Our nano-electronic device will unlock the full potential of twisted light for future optical and quantum communications,” Prof Gu said.
Their latest study has been published in Nature Communications.