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51.
Stochastic resonance in a gain--noise model of a single-mode laser driven by pump noise and quantum noise with cross-correlation between real and imaginary parts under direct signal modulation
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Stochastic resonance (SR) is studied in a gain--noise model of a
single-mode laser driven by a coloured pump noise and a quantum noise
with cross-correlation between real and imaginary parts under a
direct signal modulation. By using a linear approximation method, we
find that the SR appears during the variation of signal-to-noise
ratio (SNR) separately with the pump noise self-correlation time
\tau , the noise correlation coefficient between the real part and
the imaginary part of the quantum noise \lambdaq , the
attenuation coefficient \gamma and the deterministic steady-state
intensity I_0 . In addition, it is found that the SR can be
characterized not only by the dependence of SNR on the noise
variables of \tau and \lambdaq, but also by the
dependence of SNR on the laser system variables of \gamma and I0. Thus our investigation extends the characteristic quantity of SR
proposed before. 相似文献
52.
Output power spectrum of a single-mode laser driven by coloured pump and quantum noises with coloured correlation
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By using the linear approximation method, the output power spectrum is calculated for a single-mode laser driven by coloured pump and quantum noises with coloured correlation. We have observed that the configuration of the output power spectrum is complicated: that is, it can be of single peak, two peaks or three peaks. The configurations of the power spectrum can be transformed from one into another by changing the cross-correlation time, the cross-correlation coefficient between the two noises, and pump noise intensity. 相似文献
53.
We study the probability current of the Brownian Particles in a tilted periodic piecewise linear “saw-tooth” Potential.It is found that the stationary probability current takes on a maximum value at a given additive noise if the intensity of the multiplicative noise is appropriate and at the same time both noises are correlated;and the direction of the stationary probability current is reversed more than once upon some certain corelation intensities between both noises.It is proven that the occurrence of current reversal is only dependent on the relative intensity of the multiplicative and additive noises,but has nothing to do with the absolute intensities of the two noises. 相似文献
54.
Stochastic Resonance in a Bistable Sawtooth Potential Driven by COrrelated Multiplicative and Additive Noise 总被引:2,自引:0,他引:2
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We Present and analytical investigation of the signal-to-noise ratio(SNR)by studying the bistable sawtooth system driven by correalted Gaussian white noise.The analytic expression of the SNR is obtained.We detect some novel results,as follows.(1) Stochastic resonance(SR) always occurs in the SNR-Q (the multiplicative noise intensity)curve for the whole range of correlation coefficients.(2)There is not only resonance but also suppression and monotony in the dependence of SNR upon the additive noise intensity.(3) There are two extrema(one is minimum,the other meximum)in the SNR-b(the barrier height)curve for different multiplicative noise intensities. 相似文献
55.
Influence of the net gain on characteristic of stochastic resonance in a single-mode laser system 总被引:1,自引:0,他引:1
The phenomenon of stochastic resonance (SR) is found in a single-mode laser system driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts. When the net gain a0 changes, it is found that, 1) the shape of the curve of the signal-to-noise ratio (SNR) versus the pump noise self-correlation time τ exhibits a changing process of multiform SR, from single-peak SR, to simultaneous existence of resonances and suppressions; 2) the curve of SNR. versus signal frequency Ω experiences a complicated changing process from the monotonous descending to the simultaneous appearances of a maximum and a minimum, and finally to monotonous descending; 3) the curve of SNR versus cross-correlation coefficient between the real and imaginary parts of the quantum noise λq appears an acute single-peak SR. Therefore, the net gain ao greatly influences the characteristic of SR of laser system. 相似文献
56.
Intensity Correlation Time of a Single-Mode Laser Driven by Two Coloured Noises with Coloured Cross-Correlation with Bias Signal Modulation
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The intensity correlation time T is studied by employing a gain-noise model of a single-mode laser driven by coloured pump noise τ1 and coloured quantum noise τ2 with coloured cross-correlation τ3 with a bias signal modulation. By using the linear approximation method, we detect that a maximum (i.e. resonance) exists in the curves of the intensity correlation time T versus the noise intensities D and Q when the noise correlation coefficient A is positive; and a minimum (i.e. suppression) exists in the T - D and T - Q curves when A is negative. When A is zero, T increases monotonously with increase of D and decreases monotonically with increase of Q. Furthermore, the curve of T versus the pump noise self-correlation time τ1 is also studied. Our study shows that, no matter what the value of A is, there exist one maximum and one minimum in the T - τ1 curve. 相似文献
57.
Stochastic resonance in a single-mode laser driven by frequency modulated signal and coloured noises
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By adding frequency modulated signals to the intensity equation of
gain--noise model of the single-mode laser driven by two coloured
noises which are correlated, this paper uses the linear
approximation method to calculate the power spectrum and
signal-to-noise ratio (SNR) of the laser intensity. The results show
that the SNR appears typical stochastic resonance with the variation
of intensity of the pump noise and quantum noise. As the amplitude
of a modulated signal has effects on the SNR, it shows suppression,
monotone increasing, stochastic resonance, and multiple stochastic
resonance with the variation of the frequency of a carrier signal
and modulated signal. 相似文献
58.
Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator
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The diffusion in a harmonic oscillator driven by coloured noises
$\xi(t)$ and $\eta(t)$ with coloured cross-correlation in which
one of the noises is modulated by a biased periodic signal is
investigated. The exact expression of diffusion coefficient d as a
function of noise parameter, signal parameter, and oscillator
frequency is derived. The findings in this paper are as follows. 1)
The curves of d versus noise intensity D and d versus noises
cross-correlation time $\tau_3$ exist as two different phases. The
transition between the two phases arises from the change of the
cross-correlation coefficient $\lambda$ of the two
Ornstein--Uhlenbeck (O-U) noises. 2) Changing the value of $\tau_3$, the curves of d versus Q, the intensity of colored noise
that is modulated by the signal, can transform from a phase having a
minimum to a monotonic phase. 3) Changing the value of signal
amplitude A, d versus Q curves can transform from a phase
having a minimum to a monotonic phase. The above-mentioned results
demonstrate that a like noise-induced transition appears in the
model. 相似文献
59.
Influences of quantum noises on direct-modulated properties of 1.3-μm InGaAsP/InP laser diodes
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Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm
InGaAsP/InP laser diodes have become main light sources in fibre communication
systems recently. Influences of quantum noises on direct-modulated properties of
single-mode 1.3-μm InGaAsP/InP laser diodes are investigated in this article.
Considering the carrier and photon noises and the cross-correlation between the two
noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR)
of the direct-modulated single-mode laser system are calculated using the linear
approximation method. We find that the stochastic resonance (SR) always appears in
the dependence of the SNR on the bias current density, and is strongly affected by
the cross-correlation coefficient between the carrier and photon noises, the
frequency of modulation signal, and the photon lifetime in the laser cavity. Hence,
it is promising to use the SR mechanism to enhance the SNR of direct-modulated
InGaAsP/InP laser diodes and improve the quality of optical fibre communication
systems. 相似文献
60.
MODE-COMPETITION EFFECTS OF A TWO-MODE LASER WITH MULTIPLICATIVE COLORED NOISE WITH SATURATION EFFECTS
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The effect of multiplicative colored noise on mode-competition of the two-mode laser with saturation effects is studied, By means of linear stability analysis, and by considering τ as a small parameter, some significant conclusions have been obtained. In strong coupling, the effect of multiplicative colored noise on mode-competition is stronger than that of multiplicative white noise, and it is enhanced with the increase of noise strength. In weak coupling, the effect of multiplicative colored noise on mode-competition is weaker than that of multiplicative white noise, and it is decreased with the increase of coupling constants. 相似文献