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Secure high-speed information processing

Final Activity Report Summary - SHIP (Secure High-Speed Information Processing)

Control and synchronisation of chaotic dynamics became an area of great interest in recent years. Specific attention was given to the opportunities to exploit optical chaos to effect private or secure communications. One means for implementing such chaotic communications involves the use of semiconductor lasers subject to time-delayed optical feedback in an external cavity. It is known, in configurations with fixed external cavity length, that an eavesdropper may determine the optical feedback time-delay which thus compromises the security of such systems.

In the SHIP project, theoretical investigations showed that external cavity lasers with chaotically varying time delays were robust to eavesdropper interrogation of the time delay and thus possessed significant advantages for secure chaos-based communications. This result was of practical importance in the context of a recent successful field experiment of chaotic message transmission over an installed commercial optical fibre network.

Complementary work was also undertaken in order to use chaos to realise schemes for reconfigurable digital logic elements. The opportunity to realise that functionality using chaotic laser diodes was identified. Communications and digital logic were the cornerstones of digital information processing. The opportunity to realise these functions using a common optoelectronic device provided a means for the development of secure, high-speed information processing. The SHIP project elucidated the underlying requirements of chaos control and synchronisation to enable the convergence of chaos-based digital communications and digital logic.