Abstract

Chaos synchronization has attracted great interests because of its potential applications in secure communication. Extension to optical systems is expected to be useful in optical signal processing. Phase synchronization shows that amplitudes of coupled oscillators are chaotic but their phases become in step with a common timing characteristic. Clock timing has been a key factor in communication systems, so, synchronized phases and phase squeezing would be crucial for application to encoded communication. Phase squeezing dynamics in the self-mixing modulated coupled lasers has been recently explored [1]. Nevertheless, more experimental schemes are desired to find applications to signal processing. On the other hand, current application trend of synchronized chaos is masking chaos. In contrast, using chaos for information transmission remains one issue of concern [2]. Chaos is consisted of an infinite number of unstable periodic orbits, and thus large information capacity in transmission is possible. Along this line, synchronized chaos can serve the broadcasting source (duplicator) for large-capacity information communication. Here, new experimental results on synchronized chaos in mutually coupled microchip Nd:YVO₄ (yttrium orthovanadate) solid-state lasers operating at free-running condition are reported. Besides the exploration of the mechanism of synchronized chaos, the ways to coding chaos also have been investigated.

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