Toward Fully‐Fledged Quantum and Classical Communication Over Deployed Fiber with Up‐Conversion Module

Quantum key distribution (QKD), the of quantum secured keys useful for data encryption, is expected to have a crucial impact in next decades. However, although notable achievements accomplished last twenty years, many practical and serious challenges are limiting full deployment this novel technology current telecommunication infrastructures. In particular, co-propagation signals high-speed traffic within same optical fiber, not completely resolved, due intrinsic noise caused by high intensity classical signals. As consequence, schemes limit amount power order reduce overall link noise. ad-hoc solution restrains range possibilities large-scale QKD deployment. Here, we propose demonstrate new method, based on up-conversion assisted receiver, co-propagating light addition, compare performances scheme with an off-the-shelf equipped standard InGaAs detector, over different lengths installed fiber link. Our proposal exhibits higher tolerance comparison thus enabling secret condition 4 dB-higher power.