The significance of private and secure communications is very clear in a world experiencing political and religious divisions and ferocious competition in commercial activities. Also, in a world which increasingly relies on rapid transmission of large amounts of information, the bandwidth of these secure communications needs to be up-scaled continuously. The current solutions for secure communications are the public key cryptosystems using software techniques to achieve computational complexity. Quantum Computers have the potential to render such techniques obsolete. Another method of increasing security in communications is to use hardware complexity to hide or mask a message on a carrier that is a complex code, noisy signal or chaotic signal. These techniques, as applied chaotic laser systems are currently attracting considerable worldwide attention.

In collaboration with Macquarie University , we have proposed and are constructing a number of novel chaotic semiconductor laser systems. The Quantum Electronics group is currently conducting experiments investigating the behaviour of electronic feedback systems. We have already demonstrated that our system may be used to increase the security of communication systems based on chaotic masking. We are now turning our attention to investigations of encoding schemes, noise transfer and further improving the security of these systems.