Retroreflective Optical Communication

We are developing enabling technology for small, low signature, low cost, remote sensor tagging, or communication devices.

The approach uses optical interrogation and upload of data to a hub platform using a retroreflective, coherent optical communication system, taking advantage of local processing at the remote node. The objective of BAE Systems’ work is that the optical system will permit bi-directional communication over ranges of several km.

Retroreflectors are used to return light toward an optical source when it is inconvenient or undesirable to generate new light at the remote location. Common examples are the use of special reflective materials for safety clothing or signage, cat’s eye markers in road surfaces and measurement points in land surveying or robotic machinery.

All of these applications use passive retroreflectors, so no information is encoded into the reflected light. Active retroreflectors can be used to add information in order to establish two-way, free-space optical communication between the base station and the remote location without needing an optical source at the remote end of the link.

For military applications, valuable advantages include better link security and covertness than radio links; remote transponders with extremely low power consumption allowing long, unattended operational life; and very small size and weight for convenient and unobtrusive deployment.

The ATC is developing technology for both ends of the optical link. At remote nodes, small retromodulators having a very wide field of view are being produced. For the hub unit, optimisation of the link range will be achieved by development of an advanced optical transceiver with eye-safe output, robustness to optical impairments arising from atmospheric turbulence, and providing extremely high detection sensitivity.

Applications in military operations include reconnaissance and surveillance links, personal communications and identification. The optical base station can be located on fixed or moving platforms, including aircraft and satellites.