Laser diodes for chaotic optical data encryption

Secure communication systems based upon chaotic encryption of data have recently attracted interest. An efficient algorithm for improving the locking rate between receiver and transmitter of such a system has been reported previously K.A. Shore and D.T. Wright (1994) and we have given consideration to techniques for the control of the nonlinear dynamics of lasers in general V.N. Chizhevsky and S.I. Turovets (1994; 1993) and, in particular, laser diodes (L.N. Langley et al., 1995) which can function as practical transmitters in chaotic optical data encryption systems. An investigation is undertaken of the use of continuous optoelectronic feedback in selecting periodic dynamics in external cavity laser diodes, subject to conventional optical feedback. Other work has explored the control of chaos in external cavity laser diodes using occasional proportional feedback (G.R. Gray et al., 1993) and direct modulation (N. Watanabe and K. Karaki, 1995)