Free-Space Quantum Key Distribution

ABSTRACT: The secure transmission of digital information is of extreme importance for military and commercial applications. The need for protecting information from hostile eavesdroppers has motivated the search for novel security schemes. The current state of the art exploits quantum mechanics for the secure distribution of keys to enable the secure exchange of information. This Quantum Key Distribution (QKD) approach promises to provide a final solution to the problem by insuring unconditional security based upon the laws of quantum mechanics. Numerous experiments demonstrating QKD have been conducted in both fiber and free space configurations. While the performance of these systems in terms of data rates (key rates) and distance is below that seen in classical transmission of information, the security promised by QKD makes it an enticing technology. The last frontier for QKD is satellite to ground applications, where the need is great to have unconditionally secure method for communications. To address this potential, SA Photonics has developed the Sphinx QKD system for LEO-to-ground applications. By combining several innovative techniques to support high speed operation and tight temporal and spectral filtering, the Sphinx system provides high secure rates and supports operation during both day and nighttime. BENEFIT: The Sphinx system provides numerous benefits for both military and commercial applications. By supporting high rate secure key distribution between LEO satellites and ground terminals, a new era of secure satellite communications is possible. The absolute security enabled by Sphinx will allow reliable and secure information exchange for military, government and commercial applications. In addition, they key Sphinx technology and architecture is applicable to terrestrial Free Space Optical links as well, support secure communication needs on military bases and domestic and foreign government buildings, embassies and complexes.