Enabling Technologies for Free Space Quantum Cryptography

In this SBIR Phase-I project we aim to exploit a new invention in quantum cryptography to secure free-space optical links and networks. Unlike the techniques based on single-photon states that are limited to low bit rates and short distances, our approach is based on coherent states emitted by ordinary lasers, permitting scaling to high speeds and deployment over realistic distances. We have already demonstrated single channel speeds of 0.25 Gbps over 100 km distance in optical fiber. In this SBIR we aim to scale this technology to 2.5 Gbps over free-space distances spanning LEO and MEO spacecrafts and ground networks. We believe this technology is also applicable to encrypting data over emerging commercial free-space-optics (FSO) networks. Specifically, in Phase I we will perform the following tasks: 1) Determine optical power budgets required to achieve 2.5 Gbps encrypted data rate over LEO and MEO distances. 2) Build a laboratory prototype free-space encryption link working at 622Mbps with streaming data propagating 20-200 meters. 3) Explore combining this encryption technology with free-space quantum key distribution to achieve fully secure high-speed data transmission between spacecraft and ground stations. 4) Explore opportunities with commercial FSO equipment vendors for encrypting data on FSO networks.