South Korean research team developed world’s first integrated transmit/receive key component for wireless quantum cryptography telecommunication. By doing so, it took a step forward in commercializing wireless quantum cryptography telecommunication and implementing safe telecommunication systems towards hacking.
A research team led by Yoon Cheon-ju, who holds a Ph.D. degree, of Electronics and Telecommunications Research Institute’s (ETRI, Director Lee Sang-hoon) Optical Communication Component Research group made an announcement on the 27th that it succeeded in integrating and making current quantum cryptography telecommunication transmit/receive component, which is in a unit of meters, smaller than centimeters in size along with Korea Institute of Science and Technology (KIST).
Quantum cryptography telecommunication is a cryptography telecommunication system that guarantees perfect security. When hacking or copying is attempted, state of quantum changes which leads to information getting destroyed. It sends single photon to a receiver and forms an encryption key. It forms encryption keys for both a transmitter and a receiver through polarized light (light that has uniformed electric field) of a photon and quantum phase state.
Telecommunication component developed by the research team sends quantum signals by sending single photon at a speed of 100MHz per second. Research team implemented 4-channel light source, polarized light combination and separation module, and single photon detector as parts and modules.
This component’s biggest characteristic is its size. Research team integrated previous telecommunication component, which has gotten bigger as it was composed of bulk optical components, into single chip and reduced its width and length to about 40mm and 2mm respectively.

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<4-channel integrated polarized light combination and separation chip and module for wireless quantum telecommunication>

Low price and high stability are also one of its strengths. Until now, packaging process that creates many individual components and adjusts routes of photons was needed and this requires high cost and lowers stability. On the other hand, research team’s component has low production cost and has excellent stability.
Its performance is also outstanding. After the research team carried out a test inside its lab, its ‘quantum bit error rate’ was less than 5%. When this error rate is under 11%, it is possible to create an encryption key that makes wiretapping impossible.
Research team is planning to demonstrate wireless quantum telecommunication in an actual environment in early next year. It is going to confirm hundreds of kbps-level encryption key transmission rate and it is also going to achieve 5% of quantum bit error rate outside as well.
ETRI is predicting that this component will be used for encryption of telecommunication equipment, security network for national administrative network, security for financial network, encrypted transmission of military secrets, maintenance of data center’s secrets, and prevention of hacking on cars.
“Quantum cryptography telecommunication will be able to send and receive information in perfect security state during generations of IoT (Internet of Things).” said Yoon Cheon-ju. “We are going to carry out follow-up research on rapid long-distance wireless cryptography telecommunication and secure network for moving objects.”
Staff Reporter Kim, Youngjoon | kyj85@etnews.com