Photonic Integrated Circuits practically used for QKD
For some time now, research into Photonic Integrated Circuits (PICs) has been considered a breakthrough in QKD technology, that is expected to be produced in large quantities. In addition, the small pluggables with optical circuits are much more practical than a 19″ box. Also high speeds and energy efficiency are possible.
The Dutch company CUbIQ Technologies has now demonstrated a proof-of-concept experiment. The optical transceiver from partner company Coherent, which has the dimensions of a QSFP-28 pluggable, has been extended to achieve continuous variable (CV)-based quantum key generation with a second transceiver. The PICs can simply be plugged into the ports of the respective encryptors to save space, thus enabling the use of future-proof, tap-proof encryption – without adding a separate quantum network to the existing infrastructure.
At ECOC at the end of September 2025, these PICs for QKD over DWDM were successfully tested with HPE Juniper routers for tap-proof MACsec encryption. The quantum keys securely generated on the chip of the pluggable could be seamlessly integrated into the encryption.
Soon, such PICs will have reached market maturity and can thus offer an easily scalable solution to this threat of quantum computers for current cryptography, perhaps just in time for the maturation of quantum computers.