STATISTICAL FLUCTUATION IN A SATURATION LASER MODEL WITH CROSS-CORRELATIONS BETWEEN THE REAL AND IMAGINARY PARTS OF QUANTUM NOISE

2010 ◽  
Vol 24 (24) ◽  
pp. 4881-4888
Author(s):  
Y. H. LI ◽  
C. S. MA ◽  
D. C. MEI
Keyword(s):  
Quantum Noise ◽  
Laser System ◽  
Planck Equation ◽  
Phase Method ◽  
Statistical Fluctuation ◽  
Stationary Probability Distribution ◽  
The Real ◽  
Analytic Expressions ◽  
Cross Correlations ◽  
Laser Model

We study the effects of cross-correlations between the real and imaginary parts of quantum noise on the intensity fluctuation of a saturation laser model. By virtue of the locked phase method,we derived an approximate Fokker–Planck equation and analytic expressions of the stationary probability distribution function (SPD) of the laser system. Based on the SPD, the mean, the normalized variance, and the normalized skewness of the steady-state laser intensity are calculated numerically. The results indicate that the correlation strength of the cross-correlations between the real and imaginary parts of quantum noise increases the intensity fluctuations.

EFFECTS OF CORRELATED NOISES IN A SATURATION LASER MODEL

2006 ◽  
Vol 20 (23) ◽  
pp. 1481-1488 ◽  
Author(s):  
P. ZHU ◽  
S. B. CHEN ◽  
D. C. MEI
Keyword(s):  
Steady State ◽  
Intensity Fluctuation ◽  
Laser System ◽  
Planck Equation ◽  
Steady State Probability ◽  
Multiplicative Noises ◽  
Analytic Expressions ◽  
Laser Model ◽  
Correlation Strength ◽  
Correlated Noises

The effects of correlations between additive and multiplicative noises in a saturation laser model are investigated. The approximative Fokker–Planck equation and analytic expressions of the steady-state probability distribution function (SPD) of the laser system are derived. Based on the SPD, the normalized mean, the normalized variance, and the normalized skewness of the steady-state laser intensity are calculated numerically. Our results indicate that: (i) For the laser being operated above threshold, the correlation strength λ reduces the intensity fluctuation; (ii) For the laser being operated near threshold and below threshold, the correlation strength λ enhances the intensity fluctuation.

STATISTICAL PROPERTIES OF INTENSITY FLUCTUATION OF SATURATION LASER MODEL DRIVEN BY CROSS-CORRELATED ADDITIVE AND MULTIPLICATIVE NOISES

2010 ◽  
Vol 24 (14) ◽  
pp. 2175-2188 ◽  
Author(s):  
PING ZHU ◽  
YI JIE ZHU
Keyword(s):  
Probability Distribution ◽  
Cross Correlation ◽  
Laser Intensity ◽  
Laser System ◽  
Stationary Probability ◽  
Stationary Probability Distribution ◽  
Model Driven ◽  
Multiplicative Noises ◽  
Laser Model ◽  
The Stability

Statistical properties of the intensity fluctuation of a saturation laser model driven by cross-correlation additive and multiplicative noises are investigated. Using the Novikov theorem and the projection operator method, we obtain the analytic expressions of the stationary probability distribution Pst(I), the relaxation time Tc, and the normalized variance λ2(0) of the system. By numerical computation, we discussed the effects of the cross-correlation strength λ, the cross-correlation time τ, the quantum noise intensity D, and the pump noise intensity Q for the fluctuation of the laser intensity. Above the threshold, λ weakens the stationary probability distribution, speeds up the startup velocity of the laser system from start status to steady work, and attenuates the stability of laser intensity output; however, τ strengthens the stationary probability distribution and strengths the stability of laser intensity output; when λ < 0, τ speeds up the startup; on the contrast, when λ > 0, τ slows down the startup. D and Q make the relaxation time exhibit extremum structure, that is, the startup time possesses the least values. At the threshold, τ cannot generate the effects for the saturation laser system, λ expedites the startup velocity and weakens the stability of laser intensity output. Below threshold, the effects of λ and τ not only relate to λ and τ, but also relate to other parameters of the system.

THE INTENSITY CORRELATION TIME OF A SINGLE-MODE LASER DRIVEN BY BOTH COLORED PUMP NOISE WITH SIGNAL MODULATION AND QUANTUM NOISE WITH CROSS-CORRELATION BETWEEN ITS REAL AND IMAGINARY PARTS

2006 ◽  
Vol 20 (29) ◽  
pp. 1867-1878
Author(s):  
QING-HUA CHENG ◽  
DA-HAI XU ◽  
LI CAO ◽  
DA-JIN WU
Keyword(s):  
Correlation Time ◽  
Cross Correlation ◽  
Quantum Noise ◽  
Laser System ◽  
Single Mode ◽  
Time Correlation ◽  
Statistical Fluctuation ◽  
Intensity Correlation ◽  
Single Mode Laser ◽  
Modulation Signal

Using linear approximation method, we calculate the intensity correlation time of a single-mode laser driven by both colored pump noise with signal modulation and quantum noise with cross-correlation between its real and imaginary parts, and analyze the influence of the signal, noise and its cross-correlation form on the statistical fluctuation of the laser system. We detect that the "color" of pump noise is an important factor that affects the statistical fluctuation of the laser system. When the colored pump noise is short time correlation, within a determinate parameter range, the intensity correlation time can be prolonged, and the statistical fluctuation of the laser system can be restrained by increasing the amplitude of modulation signal. The specific frequency of input signal will result in intensity correlation time to appear maximum, and the statistical fluctuation of the laser system is least here. When the colored pump noise is long time correlation, within a determinate parameter range, the intensity correlation time can be also prolonged by increasing the frequency of modulation signal and decreasing its amplitude, and the statistical fluctuation of the laser system will decrease. In particular, when the intensity of quantum noise increases and the cross-correlation between its real and imaginary parts enhance, the intensity correlation time will prolong, and the statistical fluctuation of the laser system is restrained.

THE RELAXATION TIME OF A SINGLE-MODE LASER SYSTEM DRIVEN BY PUMP AND QUANTUM NOISES WITH REAL AND IMAGINARY PARTS CORRELATED

2009 ◽  
Vol 23 (22) ◽  
pp. 2607-2614
Author(s):  
BING WANG ◽  
YONG-XIN TANG ◽  
SHAO-PING YAN ◽  
JIAN-QIU ZHANG
Keyword(s):  
Relaxation Time ◽  
Quantum Noise ◽  
Laser System ◽  
Operator Method ◽  
Single Mode ◽  
Noise Strength ◽  
Mode Laser ◽  
The Real ◽  
Single Mode Laser ◽  
The Mean

Based on the Fokker–Planck description of a single-mode laser system and the projection operator method, the mean relaxation time T of a single-mode laser system with correlations between the real and imaginary parts of the quantum noise as well as the pump noise is studied. It is found that the mean relaxation time T increases with the increasing net gain a0 and decreases with the increasing self-saturation coefficient A. T increases with the increasing pump noise strength Q but decreases with the increasing quantum noise strength D. The mean relaxation time T increases (decreases) with the increasing pump noise self-correlation time τ if a0 > 0 (a0 < 0). T decreases with the increasing |λ| (λ is the coefficient of cross-correlation between the real and imaginary parts of the quantum noise).

scholarly journals Mid-infrared optical frequency comb in the 2.7–4.0 μm range via difference frequency generation from a compact laser system

2020 ◽  
Vol 8 ◽  
Author(s):  
Lian Zhou ◽  
Yang Liu ◽  
Gehui Xie ◽  
Chenglin Gu ◽  
Zejiang Deng ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Near Infrared ◽  
Quantum Noise ◽  
Frequency Comb ◽  
Laser System ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Average Output ◽  
Mid Infrared ◽  
Frequency Generation

Abstract We report on the generation of a mid-infrared (mid-IR) frequency comb with a maximum average output power of 250 mW and tunability in the 2.7–4.0 μm region. The approach is based on a single-stage difference frequency generation (DFG) starting from a compact Yb-doped fiber laser system. The repetition rate of the near-infrared (NIR) comb is locked at 75 MHz. The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed. Except for the intrinsic of NIR comb, environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth, which limits the precision of mid-IR dual-comb spectroscopy.

DELAYS INDUCE DIFFERENT SWITCH IN A STOCHASTIC SINGLE GENETIC REGULATION SYSTEM WITH A POSITIVE AUTOREGULATORY FEEDBACK LOOP

2013 ◽  
Vol 27 (11) ◽  
pp. 1350085 ◽  
Author(s):  
CAN-JUN WANG
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Genetic Regulation ◽  
Monomer Concentration ◽  
Planck Equation ◽  
Mean Value ◽  
Regulation System ◽  
Stationary Probability Distribution ◽  
Small Delay ◽  
Theoretical Predictions

The steady properties of a stochastic single genetic regulation system with the different time delays, which appear in the deterministic and fluctuating forces, are investigated based on the small delay time approximation method. Using the approximation probability density approach, the delayed Fokker–Planck equation is obtained. The effects of two different time delays on the stationary probability distribution and the mean value are discussed. It is found that with the time delay τ1 in the deterministic force increasing, the TF-A monomer concentration shifts from "off" state to "on" state. However, with the time delay τ2 in the fluctuating force increasing, the TF-A monomer concentration shifts from "on" state to "off" state. In the switch process, two kinds of time delays play an opposite role. The theoretical predictions are found to be in good agreement with numerical results.

scholarly journals CP VIOLATING ASYMMETRIES OF b QUARKS AND LEPTONS IN $e^+ e^-\to t\bar t$ AND SUPERSYMMETRY

1999 ◽  
Vol 14 (01) ◽  
pp. 1-23 ◽  
Author(s):  
EKATERINA CHRISTOVA
Keyword(s):  
Phase Space ◽  
Cp Violation ◽  
Numerical Results ◽  
The Real ◽  
B Quarks ◽  
Analytic Expressions

The distributions of the single decay b-quarks and leptons from [Formula: see text] assuming CP violation are reviewed. Different asymmetries, sensitive independently to CP violation in the production and in the decay, and sensitive to the real and imaginary parts of dγ and dZ are defined. The analytic expressions are general and independent on the model of CP violation. In most of them all phase space integrations are fulfilled analytically. Numerical results in the MSSM with complex couplings are presented.

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