Light is the fastest thing we know of, so it makes sense to tap into it for ultra-fast communication systems. Fiber optics do just that, allowing us to precisely guide where we want to send messages, but speed isn't the only factor – more data can be crammed into each message by "twisting" the light. Now, Australian researchers have developed a device to decode those beams that's small enough to fit over the end of a fiber optic cable.
Traditionally fiber optics tech carries information as pulses of light, and scientists are currently experimenting with increasing bandwidth by making use of the "shape" of the light as well. Twisting beams of light into a "corkscrew" shape is emerging as a particularly promising method, and the degree of twisting is known as the light's orbital angular momentum (OAM).
Rather than one wavelength being one channel of information, each "turn" of the light can encode a different value – and better still, there's a theoretically infinite number of turns, allowing much more data to be transmitted.
But that doesn't help if that information can't be decoded at the other end. Devices to do that job are generally big and bulky, but now researchers from RMIT and the University of Wollongong have developed a much smaller version.
The device works thanks to a complementary metal-oxide semiconductor (CMOS) sensor, a term you might be familiar with from the world of cameras. These chips convert incoming photons into electrons, which allows the data to be read by conventional electronics. But before the light hits the sensor, it passes through another layer that untangles the twisted light.
"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," says Haoran Ren, co-lead author of the study. "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 millimeter, our invention does this job better and fits on the end of an optical fiber."
That tiny size is key to its usefulness, as the device can be integrated into existing infrastructure. The team says it could also be used to decode quantum information sent via twisting light.
"This technology's high performance, low cost and tiny size makes it a viable application for the next generation of broadband optical communications," says Min Gu, co-author of the study. "It fits the scale of existing fiber technology and could be applied to increase the bandwidth, or potentially the processing speed, of that fiber 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."
The research was published in the journal Nature Communications.
Source: RMIT
