(LaserFocusWorld) Field tests are solving the challenges of counting photons and measuring their quantum states in quantum key distribution (QKD)-based optical transmission networks to ensure communications security.
Commercially viable QKD transmitters and receivers are available—however, they are physically large and expensive, and only suitable for very high-value security applications. The aspiration of the industry is to address these size, weight, and power (SWaP) limitations, to deliver practical quantum-secured communications that will open broader markets for consumers, commerce, and government.
A major step towards SWaP-saving is to engineer QKD on affordable chips, such as those that will fit into a smartphone. The physics is proven, but the challenge is developing small-enough devices. QKD systems are being developed in many countries, most notably in Austria, Canada, China, Japan, South Korea, Switzerland, the U.S., as well as the UK.