The hollow core fiber is only filled with air, but the safety applications of the technology can be very promising. A new type of thin, air-filled optical fiber has been shown to be particularly effective for quantum key distribution (QKD) with a fundamentally unbreakable security protocol that can play a key role in protecting sensitive data from increasingly sophisticated cyber-attacks.
BT experimented with QKD on a six-kilometer-long hollow core cable, a technology that has been developed in recent months as an alternative to traditional optical cables.
Optical fibers are usually made of solid glass fibers, which transmit the information by channeling the light signals emitted by the laser transmitters. The center of the hollow core fibers, on the other hand, is filled with air, i.e. it is actually a flexible glass tube. This configuration has been shown to be more suitable for QKD because it reduces the possibility of different signals interfering with each other and destroying the whole process.
QKD works similarly to traditional cryptography: data encrypted into an unreadable message with a cryptographic key that the recipient needs to decrypt the information. The method works by encrypting the cryptographic key on a quantum particle (or qubit), which is sent to the other person who measures the qubit to obtain the key value.
This approach is therefore of particular interest to security researchers. for because it is based on the laws of quantum physics that require qubits to collapse as soon as they are measured. This means that if a third party eavesdrops on the exchange process and measures the qubits to guess the cryptographic key, it would inevitably leave a trail of intrusion.
Cryptographers therefore use QKD. ” demonstrably “called safe. The method is expected to bring an additional level of security to data exchanges, especially as hackers are developing better and better tools to crack existing security protocols. The technology is still evolving and researchers are exploring different ways to implement QKD, but one of the best practices is to use optical cables to transmit both the cryptographic key-loaded qubits and the actual encrypted message.
However, when using traditional optical fibers, the efficiency of the protocol is limited. This is because the light signals carrying the information are likely to propagate in their wavelength as they pass through the glass, a so-called “crosstalk” effect, which causes the light channels to leak into other channels.
Therefore, the encrypted message cannot be sent over the same cable as qubits, which are extremely fragile and sensitive to crosstalk noise. According to BT, the whole process is like trying to talk in a whisper with a band.
This is the point where hollow fibers can make a big difference. In an air-filled duct, the light signals are not scattered as much and less “cross-talk” occurs between the ducts. In other words, there can be a clear difference between an encrypted stream and a weak quantum signal carrying an encryption key, even if both are on the same thread. Ultimately, therefore, hollow fibers may be more efficient candidates for QKD, as an all-in-one solution requires less infrastructure to be built.
In addition, BT has demonstrated in previous technology experiments that the transmission of light signals much faster through an air-filled core than through glass The company says data propagates up to 50 percent faster with hollow core fibers than with traditional optical cables. This means that the technology can also significantly reduce data transmission delays. a high-performance classic channel, in this case a light signal. The success of the experiment, according to Catherine White, a BT researcher, lies in the fact that both channels remained healthy, which would not be the case with conventional fibers. “In this case, we only proved the key exchange, not the encryption,” White told ZDNet.
However, the error rate of parameters from the experiment, such as the quantum bit, indicates that the system has effectively generated a key. , which can be used to protect data. And now they are working on applying the configuration to data exchange.
The next challenge will be to find out if the technology is scalable. BT tested the QKD on a six-kilometer cable. This is still far from other experiments with the protocol, in which researchers have been able to deliver quantum particles over hundreds of kilometers. Earlier this year, for example, researchers at Toshiba Europe’s Cambridge research laboratory demonstrated QKD on optical fibers longer than 600 kilometers.
White explained that all of the low latency and scattering properties of hollow core fiber used in BT’s experiment however, it is not low in loss, which is an essential property for extending the range of QKD. However, the researchers are working on fine-tuning the material to improve its performance in this regard.
“The results show that we can achieve an astonishingly low loss when tuning the fiber to a certain wavelength. This is very promising and further improvements “This means that hollow core fibers have the potential to help QKD achieve longer-than-ever ranges,” added Catherine White.
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