Satellite Quantum Communication Using Narrow-Linewidth Atomic Line Filters

ABSTRACT:Physical Sciences Inc. (PSI) proposes to build a prototype free-space optical (FSO) quantum key distribution (QKD) link that will incorporate two key innovations: 1) a narrow linewidth atomic line filter (ALF) at 780 nm based on Rubidium vapor and 2) a 780 nm laser source based on frequency doubling a telecommunications industry standard fiber laser.By improving the rejection of the solar background by a factor of over 50 compared with the current state of the art, the ALF will enable daytime operation that is currently not possible for the low Earth orbit (LEO) to ground scenario the Air Force is envisioning.The frequency doubled fiber laser source will be critical for eventual deployment on a satellite where size and reliability will be key performance parameters.Not only will this program advance the state of the art of two key component technologies, this prototype QKD link demonstrator would have significant benefit to the Air Force as a platform for evaluating both emerging state of the art hardware and novel encryption and security protocols.BENEFIT:Quantum communication promises an unconditionally secure method for information transfer. Military, financial, medical, and other institutions with sensitive data will benefit from practical improvements to quantum communication links.