  Nowadays Quantum Key Distribution represents the most mature quantum
technology, and multiple countries as well as private institutions are building
their quantum network. However, QKD devices are still far from representing a
product within everyone's reach. Indeed, limitations in terms of compatibility
with existing telecom infrastructure and limited performances in terms of
secret key rate, using non-cryogenic detection systems, are still critical. In
this work, we implemented a quantum key distribution link between Sicily
(Italy) and Malta utilizing two different Single-Photon Avalanche Diode (SPAD)
detectors. The performances of a standard commercial SPAD have been compared
with the results achieved with a new prototype of fast-gated System in a
Package (SiP) SPAD; the SiP detector has shown to be able to accomplish a
fourteen times higher key rate compared with the commercial device over the
channel showing 20 dB of losses.
