"Quantum Cryptography: This Air-Filled Fiber Optic Cable Can Transport Un-Hackable Keys, Say Researchers"
Quantum Key Distribution (QKD) is a secure communication method that uses particles of light known as photons to encode data in quantum bits, which are transmitted to a sender and receiver in the form of an encryption key. Although QKD is unbreakable in principle, attackers could still steal important information if it is not properly implemented. BT, one of the world's leading communication services companies, has been experimenting with QKD over a six-kilometer-long cable of hollow core fiber. The company has been working with this technology for the past few months to see if it would be a better alternative to traditional fiber optic cables, which are typically made of solid strands of glass that transmit information by channeling light signals emitted by laser transmitters. Hollow core fiber has a deep center filled with air that runs throughout the entire length of the cable and is enclosed in a ring of glass. This new type of optical fiber has been found to be an effective configuration for QKD because it reduces the chances of different signals interfering with each other and diminishing the entire process. Light signals in an air-filled channel do not scatter as much. There is also less crosstalk between channels in an air-filled channel, meaning the encrypted data stream and the faint quantum signal carrying the encryption key can be separated even when they are both traveling over the same fiber. Therefore, hollow core fiber could be a more efficient candidate for QKD as it requires less infrastructure. BT also demonstrated the increased speed at which light is sent when using an air-filled core. According to the company, data can travel 50 percent faster with hollow core fiber than with traditional optical cables. This article continues to discuss the concept of QKD and the use of hollow core fiber to effectively carry out QKD.