Spatio-temporal dynamics of broad area semi-conductor lasers and its characterization (original) (raw)

Spatiotemporal dynamics of dressed broad-area lasers

Quantum and Semiclassical Optics: Journal of the European Optical Society Part B, 1998

We analyse the spatiotemporal dynamics of a broad-area two-level laser in the presence of a dressing field which is coupled to an adjacent transition. The dressing field induces Rabi splitting on one of the energy levels of the laser transition, which modifies the traditional scenario of pattern formation in two-level lasers. In particular, it is observed that phase rolls appear for any sign of the cavity detuning, and that two travelling-wave patterns with different wavenumbers can coexist near the threshold for a certain range of detuning values. Reciprocally, it can be seen that the spatial dynamics alters the standard framework of electromagnetically induced gain splitting.

Time-Resolved Dynamics of Two-Dimensional Transverse Patterns in Broad Area Lasers

Physical Review Letters, 2004

We report the first direct experimental observation of the fast dynamics (nanosecond scale) of complex two-dimensional transverse patterns in broad area lasers. The laser emission bright peaks forming the transverse patterns are observed to be aperiodically flashing in time with different growing rates. These optical filaments do not move along the cross section during their lifetime, which is close to 2 ns. The experimental observations have also been reproduced by numerical integration of the Maxwell-Bloch equations.

Spatio-temporal dynamics of semiconductor lasers: Theory, modelling and analysis

Progress in Quantum Electronics, 1996

The spatio-temporal dynamics of semiconductor lasers is studied theoretically on the basis of semiclassic laser theory. The carrier dynamics is described in a density-matrix approach and the coupled set of equations of motion for the active medium and the light field are derived. Several approximafions related to separations of length and time scales are discussed, resulting in a hierarchy of model equations leading from microscopic to macroscopic levels of description. By numerically solving space-dependent coupled partial differential equations for the (complex) optical fields, the interband polarization and the charge carrier distribution functions on the various levels of the hierarchy the formation and longitudinal propagation of unstable transverse optical filamentary structures is analyzed in a model configuration for typical doubleheterostructure multi-stripe and broad-area lasers. Spectral and spatial hole burning which is observed in the simulated carrier distributions reflects the interplay between stimulated emission and the relaxation dynamics of the carrier distributions as well as the polarization. Its details are strongly influenced by the momentum and density dependence of the microscopic relaxation rates. The transverse hole burning leads to complex spatio-temporal patterns in the macroscopic intensity picture. This complex spatio-temporal dynamic behavior in multi-stripe and broad-area lasers is analyzed by various theoretical tools which allows one to quantify the degree of complexity. CONTENTS * It should be mentioned that these assumptions break down if the the scattering probabilities are strongly peaked around a single final state as is the case in pure LO-phonon scattering or for carrier-carrier scattering at low densities, where most scattering processes are in the forward direction. (57,6s) In the present case of high densities with strong large-angle carrier-carrier scattering the assumptions are well satisfied. * Strictly speaking, p, is not exactly the linear part. Due do the band gap renormalization and the density dependent dephasing rate it includes already parts which are nonlinear in the field.

Time-resolved spatiotemporal dynamics in a broad-area CO_{2} laser

Physical Review A, 2000

We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Nonordered patterns yielding boundary-determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show the limitations imposed by the boundary conditions to the theoretical predictions of the linear stability analysis.

Temporal Dynamics of Semiconductor Lasers with Optical Feedback

Physical Review Letters, 1998

We measure the temporal evolution of the intensity of an edge emitting semiconductor laser with delayed optical feedback for time spans ranging from 4.5 to 65 ns with a time resolution from 16 to 230 ps, respectively. Spectrally resolved streak camera measurements show that the fast pulsing of the total intensity is a consequence of the time delay and multimode operation of the laser. We experimentally observe that the instabilities at low frequency are generated by the interaction among different modes of the laser. [S0031-9007(98)08077-6] PACS numbers: 05.45. + b, 05.40. + j, 42.60.Mi Nonlinear systems with delayed feedback are of interest because they can be widely found in economy, biology, chemistry, and physics [1]. These systems are in principle infinite dimensional, and from this point of view, it is difficult to classify them a priori as deterministic dynamical systems because the existence and uniqueness of a solution have to be demonstrated for each particular model . It is also difficult to separate the role of noise from determinism, because complex solutions display a Gaussian-Markovian behavior as if they were solutions of a Langevin equation , thus nonconventional measurement techniques are required .

Long-term spatiotemporal dynamics of solid-state lasers and vertical-cavity surface-emitting lasers

Physical Review A, 2009

The number of Maxwell-Bloch equations describing the spatiotemporal evolution of solid-state and semiconductor-based lasers can be reduced when the temporal scales of the fields and atomic variables are very different. We demonstrate the existence of slow ͑center͒ manifolds for models of solid-state lasers ͑such as Nd:YAG͒ and vertical-cavity surface-emitting lasers and determine reduced equations in the presence of both diffraction and carrier diffusion. Two separate methods of obtaining the reduced equations are presented. Excellent agreement between the reduced models and the original equations is obtained when the slow manifolds are expanded in a perturbative series. Since stiffness is removed, the computational time for the long-term spatiotemporal dynamics of these devices can be strongly reduced, typically by 2 orders of magnitude.

Spatio-temporal dynamics in twin-stripe semiconductor lasers

Physica D: Nonlinear Phenomena, 1994

The twin-stripe semiconductor laser, a system of two evanescently coupled nonlinear oscillators, shows complex spatio-temporal behaviour. Its dynamics is studied theoretically by numerical integration of a model system of coupled partial differential equations. The overlap of the evanescent optical fields and the diffusion of charge carriers determine the amount of nonlinear transverse coupling between the laser stripes. The concept of cumulants of the bit-number of a dynamical system composed of two subsystems , and a characteristic spatio-temporal correlation function are introduced and applied to quantify the complexities in space and time as they are observed in the output signal of the twin-stripe laser. Depending on the distance between the adjacent oscillators, three dynamical regimes are identified: Sufficiently far apart, the two laser oscillators are uncoupled and the device shows a steady constant output signal. In the regime of medium coupling, randomly oscillating light pulses dominate the output signal. If both stripes are strongly coupled, both lasers oscillate with a (fixed) phase lag but chaotic intensities.

Spatiotemporal chaos in broad-area semiconductor laser

Journal of the Optical Society of America B, 1993

We study the space-time dynamical behavior of broad-area semiconductor lasers, using an extended phenomenological laser model to include transverse diffraction of the counterpropagating optical fields and transverse diffusion of carriers. Numerical results show that the profile of the output intensity exhibits spatiotemporal chaos by way of changing random filaments. A small confinement factor and/or linewidth enhancement factor can prevent instabilities. Simulations also confirm experimental results showing that a half-symmetric unstable resonator with a suitable mirror curvature restores stability.