However, my thesis about that light has any, although extreme small, radiation in any glass fibre is devastating for the idea and technique of Quantum cryptography. Which is built on the premise of NO radiation from, for example, covert data in such designed glass fibre communication.
The technique of Quantum cryptography is blown if the glass fibre, or such communication, with its data of light can be detected by its radiation.
But, as mentioned, the technique of today can not trace any radiation from glass fibre or any other light transmitted data.