Currently phenomenal research has been going on worldwide towards new generation concealed communication technology based on synchronised chaotic lasers. This has also opened up a hardware based encryption technique. In this lecture, I will convey in brief the progress of research in these directions, including the activity in BARC.
Dr. Goswami joined Laser Division, BARC in 1983 as a Scientific Officer-C after completion of one year course work in BARC Training school. He obtained Ph. D. degree (Physics) from Mumbai University in 2000 under the supervision of Dr. R. Chidambaram. His major research area includes characterization, control and application of nonlinear phenomena, in particular, in laser nonlinear dynamics. He discovered new generic features of weakly dissipative nonlinear systems, in particular, period tripling bifurcation, period quadrupling and other higher order n-tupling bifurcations. He showed that, multiple attractors, created in these n-tupling bifurcations, are self-similarly organized in the phase-space as well as in the parameter space. He also identified these stable periodic states as Gavrilov-Shilnikov-Newhouse sinks as they follow simultaneously the predictions of Gavrilov and Shilnikov and of Newhouse. He along with his collaborators have discovered (theoretically as well as experimentally) a novel nonlinear technique to reduce the number of coexisting stable states of generalized multistable systems. They have also successfully demonstrated the control of noise-induced multi-state hopping intermittency. He discovered â€˜Crisis Resonanceâ€™ that helps in destroying multistability through boundary crisis, due to resonant enlargement of unstable periodic states. Currently, his section has developed an experimental facility for concealed communication through optical chaotic carrier. In this facility, successful concealed transmission of GHz signals through 25 km optical fibre spool has been regularly demonstrated. Similar experimental facilities are being developed for real time digital transmission as well as for optical chaos cryptography.