A group of German, Swiss and UK scientists working at the Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) in Sydney University have found an energy-efficient way of using a single laser to transfer data down a 50km long single-mode fibre optic cable at speeds of up to 26Tbps (Terabits per second) (roughly equivilant to 400 million people making a phone call), which was previously thought to be impossible.

The solution came from a technology that is more often associated with wireless networking ( Wi-Fi ) and Mobile Broadband ( WiMAX , LTE ) systems - Orthogonal Frequency-Division Multiplexing (OFDM). This allowed the scientists to split a single laser down to 325 optical frequencies and via a narrow spectral band of wavelengths (from 1,533–1,565.5nm). The data can then be broken up and sent in parallel streams via the different frequencies.


Ben Eggleton notes that higher transfer speeds of up to 109Tbps have been achieved before by scientists working in Japan, although that method required multiple lasers. However, using multiple lasers isn't cheap, both in terms of infrastructure and energy consumption.

Eggleton claims that energy consumption in particular is growing at the same rate as the internet and "doubling every 18 months". In approximately 10 years time that energy usage, unless it's tackled, could become a very serious problem for everybody.

Naturally being able to both transmit and decode huge amounts of data via a single laser would be a huge benefit, especially to international fibre optic and undersea cable connectivity. It could cut energy usage and may even help to reduce the bandwidth costs of ordinary broadband ISPs and thus consumers.