Scientists may have made a breakthrough in quantum computing. They've created a new approach to the construction of a quantum communication system for secure data exchange.
Making sure that information is secure is becoming an important issue when it comes to the safety of large companies, banks and defense enterprises. Even small business and individual users, however, need to be assured that their information is safe. Unfortunately, the current data encryption algorithms used for protecting data are imperfect.
There's another way to secure information, however. Using quantum physics could actually make data transmission completely immune to hacker attacks in the future. More specifically, information in a quantum channel is carried by single photons that change irreversibly once an eavesdropper attempts to intercept them.
In this latest study, researchers found a new way to effectively generate and distribute quantum bits. This new technique is the first system in Russia, and it can actually compete with the best existing analogues, and even makes it possible to share quantum signals via optical fiber across 250 kilometers in distance.
"To transmit quantum signals, we use the so-called side frequencies," said Artur Gleim, head of the Quantum Information Center at ITMO University. "This unique approach gives us a number of advantages, such as considerable simplification of the device architecture and large pass-through capacity of the quantum channel. In terms of bit rate and operating distance, our system is comparable to absolute champions in the field of quantum communications."
In order to actually encode quantum bits in the system, laser radiation is directed into the electro-optical phase modulator, a special device. Inside the modulator, the central carrier wave emitted by the laser is split into several independent waves. After the signal is transmitted through the cable, the same splitting occurs on the receiver end. And depending on the phase shift of the waves created by the sender and the receiver, the waves will either enhance or cancel each other out. The pattern generated by the overlapping wave phases is then converted to 1 and 0.
Researchers were actually able to obtain high stability of relative phase shifts of the signal in the system. This could be huge for the future of quantum computing. Currently, researchers want to create a full-fledged quantum cryptographic system.
The findings were published in the April edition of Optics Express.
