S. Yoshimori

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We experimentally demonstrate random bit generation using multi-bit samples of bandwidth-enhanced chaos in semiconductor lasers. Chaotic fluctuation of laser output is generated in a semiconductor laser with optical feedback and the chaotic output is injected into a second semiconductor laser to obtain a chaotic intensity signal with bandwidth enhanced up(More)
We have achieved dual synchronization of chaos in two pairs of one-way coupled Nd:YVO4 microchip lasers, using only one transmission channel, by experiment and numerical calculation. We observed the individual synchronization of chaos in each pair of two lasers by adjusting the optical frequencies for injection locking between the corresponding pairs. The(More)
We demonstrate the dual synchronization of chaos in two pairs of one-way coupled Colpitts electronic oscillators by both experiment and numerical simulation. We use the cross coupling method, where the difference in voltage between the sum of two master oscillators and one slave oscillator is injected into the other slave oscillator as an electrical(More)
We experimentally demonstrate a chaotic on-off keying method for secure communications by using chaos synchronization in two microchip lasers. The output of the microchip laser in the transmitter is externally modulated with an acousto-optic modulator at ~4 MHz . One encodes a digital message in the chaotic carrier by turning the modulation on and off at(More)
We experimentally demonstrate blind source separation of chaos generated in Nd:YVO(4) microchip solid-state lasers by using independent component analysis. Two chaotic source signals are linearly mixed with randomly selected mixing ratio and independent component analysis is applied for the mixed signals to extract the source signals. We investigate blind(More)
We demonstrate wavelength division multiplexing with chaotic subcarriers in two pairs of one-way-coupled Nd:YVO4 microchip lasers. Two individual digital messages are encoded on two chaotic carriers with different wavelengths in two transmitters by the chaotic masking method, and the mixed signals are sent to two receivers. Dual synchronization of chaos is(More)
We experimentally and numerically demonstrate the dual synchronization of chaos in two pairs of one-way-coupled Mackey-Glass electronic circuits with time-delayed feedback. The outputs of the two drive circuits are mixed and used both for the feedback signal to the two drive circuits and for the transmission signal to the two response circuits. We(More)
We experimentally demonstrate synchronization of chaos in one-way coupled He-Ne lasers with optical feedback. We observe different types of synchronization such as identical synchronization, inverse synchronization, and random amplification. These dynamics are maintained only for a short duration of several hundred milliseconds. We also observe generalized(More)
Local conditional Lyapunov exponents are introduced and plotted in dynamical phase space to visualize the local susceptibility of the Lorenz system driven by chaos and noise signals when the system produces consistent response outputs. The dependence of the distribution of the local conditional Lyapunov exponent on changes in the drive signal is(More)
We have investigated the transient characteristics of two types of chaos synchronization in a semiconductor laser subject to optical feedback: complete synchronization and strong injection locking-type synchronization. We have calculated the statistical distribution of the transient response time of synchronization when the initial position in the starting(More)