Aiming to provide unconditionally secure quantum communication

The use of quantum computers will lead to instant decoding of traditional cryptogenic communications, creating strong demand for new cryptogenic communication technology in IoT, automated driving, telemedicine, finance, military, and other areas where high levels of security are crucial.QWAVE Dynamics performs research and development of socially achievable long-distance quantum communication which guarantees unconditional security and aims to commercialize such technology by establishing a startup company.

news

WHO WE ARE

Current cryptographic communication utilizes prime factorization, requiring significant calculation time for decryption even with state-of-the-art computers, ensuring security of the communication through the time required for such decryption.

However, calculation speeds of quantum computers currently being developed are expected to be exponentially faster than our newest computers today, exposing traditional cryptographic communication to increased risk, creating strong demand for new cryptographic communication technology in IoT, automated driving, telemedicine, finance, military, and other areas where high levels of security are crucial.

Multiple research institutions are therefore researching quantum communication based on quantum mechanics. While quantum communication theoretically makes it absolutely impossible to tap, the distance covered is currently limited to several tens of kilometers, falling short of the required span of several hundreds or thousands of kilometers required for full-scale application in society.

QWAVE Dynamics cooperates with domestic and foreign research institutions to research and develop quantum repeaters required to achieve such long-distance communications and aims to achieve commercial viability in the near future.

OUR RESEARCH

Quantum repeaters require the combination of four core elemental technologies: 1) entangled photon source, which emits light for quantum communication; 2) quantum memory, which temporarily stores quantum states to permit transmission through optic fibers until quantum measurement to achieve long distance communication; 3) wavelength conversion and 4) frequency stabilization, which together connects photon source (communication wavelength ~ 1.5um) and memory wavelength (visible light to infrared). Past R&D efforts by various research groups were limited to one or two elemental technologies, making us the first player globally to engage in system design and development which integrates these elemental technologies.

1ENTANGLED PHOTON SOURCE

To be linked to memory, a quantum entangled photon source with MHz-level spectral width is required. Through our research, this was made possible by introducing an optical cavity. The cavity photon source also generates (laser-like) enhanced photon flux which can be used as high bit rate photon sources. We were the first to efficiently generate a narrowband telecommunication wavelength two-photon source.

Entangled photon source

2QUANTUM MEMORY

Memories which can be utilized for wavelength multiplexing and/or time division multiplexing to enhance communication rate are desirable. We are one of only a few groups which possesses advanced control technology including high frequency stabilization of control lasers under 1 kHz, which is required for highly multiplexing memory. Our memory development using solid state quantum memory allowed us to prove quantum correlation between memory and emitted photons (Nature Communications 6,8955(2015)).

Quantum memory

3WAVELENGTH CONVERSION

Wavelength conversion is crucial for highly efficient absorption/storage of light from telecommunication wavelength photon source into quantum memory. Production of a wavelength conversion device has already been implemented (Nature Communications 6,8955(2015)). We aim to optimize wavelength conversion within an integrated system going forward.

Wavelength conversion

4FREQUENCY STABILIZATION

Frequency stabilization is a crucial element which provides a steady connection between the memory and the photon source. The memory transition frequency has extremely narrow linewidth (kHz-MHz), making slight fluctuations in photon source and/or wavelength conversion drastically reduce efficiency. We have already achieved long-term stability under 1 kHz and are aiming to proceed to creating integrated systems and compact systems. Each element, serving as part of a whole, has been developed under our design which allows for seamless connection. We plan to perform integration through optical fiber transmission in our laboratories and proceed to pilot systems using existing urban optical fiber networks.

FREQUENCY STABILIZATION

TEAM

Card image cap

Tomoyuki Horikiri

Associate Professor, Faculty of Engineering, Yokohama National University
2006
Research Fellow for Young Scientists, Japan Society for the Promotion of Science

2007
Ph.D., Department of Physics, Graduate School of Science, the University of Tokyo

2008-2014
Researcher, National Institute of Informatics. Researched quantum repeaters and exciton-polariton condensation at Stanford University

2014
Associate Professor, Faculty of Engineering, Yokohama National University
Card image cap

Kohei Ikeda

Graduate School of Engineering
Yokohama National University
Card image cap

Shuhei Tamura

Graduate School of Engineering
Yokohama National University
Card image cap

Kazuya Niizeki

Graduate School of Engineering
Yokohama National University
Card image cap

Mizuka Kadoya

Research Assistant, Graduate School of Engineering
Yokohama National University

PROJECT

Project Name
QWAVE Dynamics
Project Leader
Tomoyuki Horikiri
Laboratory
Room S-305, Integrated Research Ward, 79-5 Tokiwadai, Hodogaya-ku, Yokohama-shi, Kanagawa 240-8510 Japan

CONTACT

  • E-mail contact@qwave-dynamics.com
  • Phone +81-45-339-3356
  • Address Room S-305,
    Integrated Research Ward, 79-5 Tokiwadai, Hodogaya-ku, Yokohama-shi, Kanagawa
    240-8510 Japan