Optimal operating conditions for external cavity semiconductor laser optical chaos communication system

Priyadarshi, S.; Pierce, I.; Hong, Yifeng; Shore, K.A.

doi:10.1088/0268-1242/27/9/094002

Cited by 8 publications

(2 citation statements)

References 21 publications

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“…However use of a very strong message may compromise the privacy of the message transmission. It is possible to identify optimized regimes of operations where those requirements are balanced 96 . The privacy of chaos communications rests on hardware keys and notably the device parameters of the transmitter and receiver lasers which need to be rather closely matched to achieve high-quality synchronization.…”

Section: Optimised Communications and Transmission Securitymentioning

confidence: 99%

Physics and applications of laser diode chaos

Sciamanna¹,

Shore²

2015

Nature Photon

598

327

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-An overview of chaos in laser diodes is provided which surveys experimental achievements in the area and explains the theory behind the phenomenon. The fundamental physics underpinning this behaviour and also the opportunities for harnessing laser diode chaos for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.The emergence of irregular pulsations and dynamical instabilities from a laser were first noted in the very early stages of the laser development. Pulses whose amplitude "vary in an erratic manner" were reported in the output of the ruby solid-state laser 1 [ Fig. 1 a] and then found in numerical simulations 2 . However the lack of knowledge of what would later be termed "chaos" resulted in these initial observations being either left unexplained or wrongly attributed to noise.The situation changed in the late 1960s with the discovery of sensitivity to initial conditions by Lorenz 3 , later popularized as the "butterfly effect". As illustrated in Fig. 1 (b), numerical simulations of a deterministic model of only three nonlinear equations showed an irregular pulsing with a remarkable feature: the state variables evolve along very different trajectories despite starting from approximately the same initial values [ Fig. 1 b]. The distance δ(t) between nearby trajectories diverges exponentially : δ(t) = δ(0) exp(λt) provided that λ, the effective Lyapunov exponent of the dynamical system, is positive. Consequently such systems are unpredictable in the long term. Plotted in the x-y-z phase space of the state variables, the trajectories converge to an "attractor" which has the geometric property of being bounded in space despite the exponential divergence of nearby trajectories [ Fig. 1 c]. Such attractors are found to have a fractional dimension 4 and are thus termed strange. Aperiodicity, sensitive dependency to initial conditions and strangeness are commonly considered as the main properties for "chaos" The fields of laser physics and chaos theory developed independently until 1975 8 when Haken discovered a striking analogy between the Lorenz equations that model fluid convection and the MaxwellBloch equations modelling light-matter interaction in single-mode lasers. The nonlinear interaction between the wave propagation in the laser cavity (represented by the electric field E) and radiative recombination producing macroscopic polarization (encapsulated in the polarization P and carrier inversion N) yield similar dynamical instabilities to those found in the Lorenz equations. More specifically, in addition to the conventional laser threshold, Haken suggested a second threshold would exist above which "spiking occurs ...

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Section: Optimised Communications and Transmission Securitymentioning

confidence: 99%

Physics and applications of laser diode chaos

Sciamanna¹,

Shore²

2015

Nature Photon

598

327

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“…Feedback is also used in controlling the dynamic systems with various modulation types [56][57][58]. Another use of feedback is to achieve wavelength stability [59] of wavelength division multiplexing (WDM) systems through the adjustment of cross-correlation level by setting up the DC bias current [60].…”

Section: Introductionmentioning

confidence: 99%

Gain and coherence collapse condition for a laser diode with optoelectronic feedback using Volterra series

Yıldırım¹,

Canbolat²

2016

Turk J Elec Eng & Comp Sci

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Four-tone small signal analysis was performed for a nonlinear optoelectronic feedback laser diode system. In the analysis, Volterra power series up to second-order opening, the second kernel for the output intermodulation distortion (IMD) analysis was performed. The components of the alternative IMD frequency were selected for analysis. These are the four IMD frequency components. The variation of IMD frequency component amplitudes was investigated under various values of delay-time (t0) and the feedback gain constant (K). The feedback values and the critical frequencies, at which the coherence collapse or chaos occur, were also determined.

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