How will QKD be a benefit to optical networks in the short term?

Optical networks are required for QKD. Satellite solutions indeed exist, but are expensive and much less flexible if you compare it with fibre solution. At the end of the day, QKD will consolidate as an additional service for optical networks. Besides this, QKD needs optical technologies, such as single-photon detectors or photon generators, that can increase market products demand and research.

And we must not forget QKD is the first step in a more general Quantum Communications path. The technologies, service models and management mechanisms applicable to QKD will be the foundation for future Quantum Communications

What are/will be the challenges and/or risks of implementing QKD in optical networks?

The main challenge that QKD solutions face today is that we are using what is still a quite delicate technology, very much dependent on direct optical transmission, so it is limited in distance. Until quantum repeaters are available and/or longer distances become possible, the accepted solution for overcoming this limitation is the use of intermediate “trusted nodes” to go beyond current physical fiber limits. The bootstrap authentication of the service channel is also challenging because it cannot be based on the quantum channel itself, what imply temporary risk windows.

What does the future look like within the quantum communications and optical networks space?

QKD is the first quantum communications application. It is an ad-hoc solution for a specific problem (key distribution). A generalized solution that allows storing, transmitting, and processing qbits without collapsing or destroying them will trigger a new revolution on ITC. For example, Quantum Computers interconnected to make distributed computing and operations as classic computers do today. Optical networks are the best-positioned medium for quantum communication, based on their nature and the results already achieved by QKD solutions.