Mar 1 2019
Hunting for a higher order of security during data transmission, governments and other organizations worldwide are investing in and building technologies associated with quantum communication and interrelated encryption methods. Researchers are studying how these new systems—which, theoretically, would deliver unhackable communication channels—can be incorporated into current and future fiber-optic networks.
A study conducted at the National Institute of Information and Communications Technology in Japan, by a team that includes Senior Visiting Researcher Tobias A. Eriksson, holds promise for finding solutions to one of the major challenges for this application: how to realize secure communication using uninterruptedly variable quantum key distribution. Often shortened as QKD, this technique is the continuous exchange of encryption keys, produced with quantum technology, for encrypting data being conveyed between two or more parties.
Eriksson and his colleagues say the main hurdle for this application is noise created by fiber amplifiers on present-day generation single-mode fiber systems. Their study involved investigating how to manipulate multicore fiber-optic technology that is projected to be used in future transmission networks. They will present a paper at the OFC: The Optical Fiber Communications Conference and Exhibition that is held from March 3rd to 7th in San Diego, California., U.S.A.,
As the name indicates, multicore fiber-optic systems make use of numerous fiber cores in a single strand through which data can be conveyed. In existing fiber networks, each strand typically has just one core.
Secure communication is one of the hardest challenges right now and many of the current encryption methods may someday easily be broken by algorithms designed for quantum computers. One reason we haven't seen commercial deployment of QKD is that the technology is not compatible with current network architecture.
Tobias A. Eriksson, Senior Visiting Researcher, National Institute of Information and Communications Technology.
As multicore fiber started to be deployed in the future, Eriksson said, scientists are studying how that technology could be harnessed to unravel the encryption issue.
The question we asked ourselves is whether the spatial dimensions of multicore fibers can be exploited for co-propagation of classical and quantum signals. What we found is that the classical channels can be transmitted completely oblivious of the quantum signals, which in single-mode fiber is not possible since the amplifier noise kills the quantum channels.
Tobias A. Eriksson, Senior Visiting Researcher, National Institute of Information and Communications Technology.
Eriksson’s team measured the extra noise from crosstalk between the conventional and the quantum channels, using 19-core fiber. They learned that this technique has the probability to support 341 QKD channels, having 5 GHz spacing between wavelengths of 1537 nm and 1563 nm.
The team’s technical outcomes are mentioned in a paper to be presented in San Diego at the OFC meeting. They stated that when the quantum channels are using an exclusive core of a multicore fiber, network operators can evade the noise produced by core-to-core crosstalk by ensuring that the wavelengths of the quantum signals from QKD lie in the guard-band between the conventional channels that transport data. This simple solution solves the issue of multiplexing of quantum and conventional channels and avoids adding new components for the conventional communication channels.