free space optical-is it the future of communication?

So far, optical fibres are the pinnacle of data transfer performance across large distances, but DARPA is not satisfied being dependant on wired technology, and has commissioned Raytheon BBN Technologies to develop a new photon-based optical network.

Part of DARPA’s Information in a Photon program – which is focussed on both communication and imaging – the new system promises to be able to deliver very large amounts of data much faster than today’s optical networks, and in fact, can even send between Earth and space.

Scientists at Raytheon BBN Technologies are hoping to be able to use free-space optical (FSO) communication to its maximum potential. FSO are types of lasers that can transmit and receive data between two points, without them being connected physically by fibre optic cables. The technology, quite futuristic, has quite a few hurdles it needs to cross before it becomes mainstream, such as strength, range and decay of laser signals, climate and radiation interference, and more.

Raytheon is working to create photon networks will replace today’s optical communications technologies: “The idea is to significantly increase power management, speed and reach on free space optical communication links, including far-field links used in deep space”

Apart from communication, the program’s imaging goal is also of major interest to Raytheon BBN, who are working with the University of Virginia in a project called Fundamental Information Capacity of Electromagnetism with Squeezing and Spatial Entanglement, to see just how far imaging technology can be developed within the fuzzy probabilistic laws of quantum physics: “We have set out to define new quantum states of light and subsequent detection methods from which we can obtain far more image information from a lot less light”

DARPA had a bit to say about the team’s work: “Recent progress on the information capacity of optical communications has largely focused on novel 'spectrally dense modulation' techniques for increasing the spectral information efficiency of these channels. Recent demonstrations approaching 10 bits/sec/Hz in fiber suggest that similar techniques may also be successfully employed for FSO applications.”