analysis of the laser optoelectronic oscillator in Chap. 3 and in the following
chapters.
After brief description of two principles operation for internal and external
approaches, we discuss its structural realization. The complexity of both approaches
is related to nonstandard way of description of nonlinear method modulation for
internal (direct) structure and the utilization of specific Mach–Zehnder modulator for
the first stage on external modulation: the phase modulation in the optical channels
of the external MZ modulator, and (at the second modulation stage) conversion (after
the fiber optical delay line) of the phase-modulated laser emission into the
amplitude-modulated radio-frequency signal in the nonlinear photodetector.
Chapter 4 is the logical continuation of OEO investigation, in which we consider
that the laser is the main element defining the dynamic and noise properties of OEO.
In this interpretation, OEO is represented as the quantum generator spanned by the
positive feedback: the optoelectronic network containing the optical fiber, the
photodetector, the RF filter, and the RF amplifier.
Sections of the Chap. 4 are devoted to model formation of the quantum generator,
for which we use the semiclassical theory based on the dipole representation of the
laser in double-level approximation. For formation of differential equations (DE) in
quasi-stationary mode, we consider the DE system, which consists of three differential equations. This DE system establishes a connection between the active
medium polarization, the electromagnetic field strength, the inversed population of
particles on upper and lower energy levels, and pumping, taking into account the Qfactors of the optical resonator and the emission spectral line of the active medium
and the population inertial properties. Examination of this system of nonlinear DEs
with inertial properties allows formation of the laser analog model in the dipole
approximation.
The analysis of the self-oscillating system (SOS) of the laser model is performed,
for which we introduce the operator transfer function, the nonlinear element
(NE) and execute the analysis of nonlinear properties. The special role is paid at
laser system analysis to investigation of inertial nonlinear QWLD at its operation in
quasi-stationary mode with the high excess of pumping current over its threshold
value. Investigation of oscillation excitation conditions and oscillation existence
conditions in the OWLD steady-state is performed.
The one section of the Chap. 4 is devoted to results’ presentation of the nonlinear
fourth-order DE solution for the laser model in the dipole approximation. The plots
of realizations of oscillating processes for two types of nonlinearities are analyzed.
Results of computer solution for the quasi-stationary mode of laser generation are
presented for fourth-order DE at linear-hyperbolic inertial nonlinearity of the active
medium. Numerical calculation results on the base of the symbolic equation solution
are discussed for determination of resonance characteristics in the steady-state mode.
Results of nonlinear DE equations and resonance characteristics at high power
density in the optical resonator are described. Section of the Chap. 4 contains the
main conclusions.
Chapter 5 is devoted to the main features of OEO. The optoelectronic oscillator is
considered as the self-oscillating laser system with modulation, which is spanned by
1 Introduction
7
chapters.
After brief description of two principles operation for internal and external
approaches, we discuss its structural realization. The complexity of both approaches
is related to nonstandard way of description of nonlinear method modulation for
internal (direct) structure and the utilization of specific Mach–Zehnder modulator for
the first stage on external modulation: the phase modulation in the optical channels
of the external MZ modulator, and (at the second modulation stage) conversion (after
the fiber optical delay line) of the phase-modulated laser emission into the
amplitude-modulated radio-frequency signal in the nonlinear photodetector.
Chapter 4 is the logical continuation of OEO investigation, in which we consider
that the laser is the main element defining the dynamic and noise properties of OEO.
In this interpretation, OEO is represented as the quantum generator spanned by the
positive feedback: the optoelectronic network containing the optical fiber, the
photodetector, the RF filter, and the RF amplifier.
Sections of the Chap. 4 are devoted to model formation of the quantum generator,
for which we use the semiclassical theory based on the dipole representation of the
laser in double-level approximation. For formation of differential equations (DE) in
quasi-stationary mode, we consider the DE system, which consists of three differential equations. This DE system establishes a connection between the active
medium polarization, the electromagnetic field strength, the inversed population of
particles on upper and lower energy levels, and pumping, taking into account the Qfactors of the optical resonator and the emission spectral line of the active medium
and the population inertial properties. Examination of this system of nonlinear DEs
with inertial properties allows formation of the laser analog model in the dipole
approximation.
The analysis of the self-oscillating system (SOS) of the laser model is performed,
for which we introduce the operator transfer function, the nonlinear element
(NE) and execute the analysis of nonlinear properties. The special role is paid at
laser system analysis to investigation of inertial nonlinear QWLD at its operation in
quasi-stationary mode with the high excess of pumping current over its threshold
value. Investigation of oscillation excitation conditions and oscillation existence
conditions in the OWLD steady-state is performed.
The one section of the Chap. 4 is devoted to results’ presentation of the nonlinear
fourth-order DE solution for the laser model in the dipole approximation. The plots
of realizations of oscillating processes for two types of nonlinearities are analyzed.
Results of computer solution for the quasi-stationary mode of laser generation are
presented for fourth-order DE at linear-hyperbolic inertial nonlinearity of the active
medium. Numerical calculation results on the base of the symbolic equation solution
are discussed for determination of resonance characteristics in the steady-state mode.
Results of nonlinear DE equations and resonance characteristics at high power
density in the optical resonator are described. Section of the Chap. 4 contains the
main conclusions.
Chapter 5 is devoted to the main features of OEO. The optoelectronic oscillator is
considered as the self-oscillating laser system with modulation, which is spanned by
1 Introduction
7