Exchanging Information Securely Using Quantum Communication In Future Fiber-Optic Networks

Searching for better security during data transmission, governments and
other organizations around the world have been investing in and
developing technologies related to quantum communication and related
encryption methods. Researchers are looking at how these new
systems--which, in theory, would provide unhackable communication
channels--can be integrated into existing and future fiber-optic
networks.

Research 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 solving one of the key challenges
for this application: how to achieve secure communication using
continuously variable quantum key distribution. Often abbreviated as
QKD, this method is the ongoing exchange of encryption keys, generated
with quantum technology, for encrypting data being transferred between
two or more parties.

In a paper to be presented at the OFC: The Optical Fiber Communications
Conference and Exhibition being held 3-7 March in San Diego, Calif.,
U.S.A., Eriksson and his colleagues say the primary stumbling block for
this application is noise generated by fiber amplifiers on current
generation single-mode fiber systems. Their research involved exploring
how to exploit multicore fiber-optic technology that is expected to be
used in future transmission networks.

As the name suggests, multicore fiber-optic systems use multiple fiber
cores in a single strand through which data can be transmitted. In
today's fiber networks, each strand usually has only 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," Eriksson says. "One reason
we haven't seen commercial deployment of QKD is that the technology is
not compatible with current network architecture."

As multicore fiber begins to be deployed in the future, Eriksson said,
researchers are looking at how that technology could be harnessed to
solve the encryption problem.

"The question we asked ourselves is whether the spatial dimensions of
multicore fibers can be exploited for co-propagation of classical and
quantum signals," Eriksson said. "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."

Eriksson’s team measured the excess noise from crosstalk between the
classical and the quantum channels, using 19-core fiber. They found that
this approach has the potential to support 341 QKD channels, with 5 GHz
spacing between wavelengths of 1537 nm and 1563 nm.

The team’s technical results are outlined in a paper to be presented in
San Diego at the OFC meeting. The group reported that when the quantum
channels are using a dedicated core of a multicore fiber, network
operators can avoid the noise generated by core-to-core crosstalk by
making sure that the wavelengths of the quantum signals from QKD lie in
the guard-band between the classical channels that carry data. This
simple solution solves the problem of multiplexing of quantum and
classical channels and avoids introducing new components for the
classical communication channels.

Hear from the research team: “Inter-core Crosstalk Impact of
Classical Channels on CV-QKD in Multicore Fiber Transmission” by Tobias
A. Eriksson, Benjamin J. Puttnam, Georg Rademacher, Ruben S. Luis,
Masahiro Takeoka, Yoshinari Awaji, Masahide Sasaki, Naoya Wada will take
place at 8:00 a.m. on Thursday, 7 March in Room 9 of the San Diego
Convention Center.

MEDIA REGISTRATION: Media/analyst registration for OFC 2019 can
be accessed online. Further information is available on the event
website at OFC, including travel details.

About OFC

The Optical Fiber Conference and Exhibition (OFC) is
the largest global conference and exhibition for optical communications
and networking professionals. For more than 40 years, OFC has drawn
attendees from all corners of the globe to meet and greet, teach and
learn, make connections and move business forward.

OFC includes dynamic business programming, an exhibition of more than
700 companies, and high impact peer-reviewed research that, combined,
showcase the trends and pulse of the entire optical networking and
communications industry. OFC is managed by The Optical Society (OSA) and
co-sponsored by OSA, the IEEE Communications Society (IEEE/ComSoc), and
the IEEE Photonics Society. OFC 2019 will be held from 3-7 March 2019 at
the San Diego Convention Center, California, USA. Follow @OFCConference,
learn more at OFC
Community LinkedIn, and watch highlights on OFC
YouTube.

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