Robustness of vectorial laser systems (original) (raw)
Polarization dependence of the effect of external optical feedback on semiconductor lasers
Proceedings of SPIE - The International Society for Optical Engineering
We present an extension of an early work on external optical feedback in semiconductor lasers. A more general formalism has been developed, which takes into consideration the anisotropy properties of an external cavity. The expressions are derived for description of the feedback phenomena in a system composed of a laser diode and a Fabry-Perot cavity which is optically birefringent. We show that the emission behavior of such a system can be strongly affected by the polarization states of the feedback waves, and that therefore multiple solutions become possible for stabilization of a composite mode. Particular attention is paid to the angle-dependent phase condition. Examples are given for a laser emitting at the wavelength of 1.54 µm and for an external cavity made of a quartz crystal.
Threshold behavior of a laser with nonorthogonal polarization modes
Journal of the Optical Society of America B, 2002
We investigate experimentally and theoretically the influence of the excess quantum noise in a laser on the laser's input-output curve near threshold. As an experimental system we use a He-Xe gas laser with nonorthogonal polarization modes. We observe that the excess quantum noise is absent far below threshold and steadily builds up as threshold is approached. The excess noise is fully developed when the mode that (above threshold) becomes the lasing mode dominates in power the other, nonlasing, modes. This situation may already occur considerably below threshold, namely, when the hot-cavity photon lifetime of the dominant mode exceeds the coloring time of the excess noise.
Stability, of polarized modes in a quasi-isotropic laser: experimental confirmation
Journal of the Optical Society of America B, 1991
The analysis of the stability of the polarization modes of a quasi-isotropic laser is extended. The theory predicts the existence of catastrophes in the hysteresis loop of polarization versus frequency. Allowance is made for a weak cavity birefringence. Experiments with a He-Ne laser that operates at 3.39 ,tm quantitatively confirm the dependence of the hysteresis on gain, including the previously unidentified catastrophes.
Journal of Optics B: Quantum and Semiclassical Optics, 2003
We study theoretically the polarization dynamics of a new type of quantum oscillator that is based on the two-photon stimulated emission process in the presence of a magnetic field of arbitrary orientation. Both cases of cascade (small intermediate-state atomic detuning) and two-photon (large atomic detuning) lasers are considered. The primary goal of this work is to investigate the origin of recently observed polarization instabilities in a two-photon laser (Pfister et al 2001 Phys. Rev. Lett. 86 4512) using a highly simplified model. It is found that the two-photon laser can emit linearly polarized radiation with its plane of polarization orthogonal to the direction of the magnetic field at small magnetic field strengths. It can also emit elliptically polarized radiation over a large range of magnetic field strengths and orientations. When the magnetic field deviates from a direction perpendicular to the laser cavity axis periodic instabilities can appear through a Hopf bifurcation. This dynamic regime could have contributed to the polarization instabilities observed in the experiment.
Deterministic polarization chaos from a laser diode
Nature Photonics, 2012
Fifty years after the invention of the laser diode and fourty years after the report of the butterfly effect -i.e. the unpredictability of deterministic chaos, it is said that a laser diode behaves like a damped nonlinear oscillator. Hence no chaos can be generated unless with additional forcing or parameter modulation. Here we report the first counter-example of a free-running laser diode generating chaos. The underlying physics is a nonlinear coupling between two elliptically polarized modes in a vertical-cavity surface-emitting laser.
Vectorial bistability in a quasi-isotropic laser
Journal de Physique, 1986
2014 Nous montrons théoriquement et expérimentalement que le domaine de bistabilité vectorielle observable lors du basculement de polarisation dans un laser quasiisotrope diminue quand l'intensité de la lumière augmente. Abstract.2014 The domain of vectorial bistability observable in the polarization flip of a quasi-isotropic laser is theoretically and experimentally shown to decrease when light intensity increases.
Polarization modes in a quasi-isotropic laser: a general anisotropy model with applications
Journal of the Optical Society of America B, 1992
We present a model for the polarization states of a quasi-isotropic laser. The model includes the polarization competition among the gain medium, general cavity anisotropies, and the anisotropy arising from weak but arbitrarily polarized feedback. Three examples of linearly polarized feedback are given, one with the axes of the internal and external anisotropies parallel to each other and two other examples with the axes inclined at 45°. The new calculations are in agreement both with earlier calculations based on a more restricted model and with existing experimental results for a He-Ne laser operating at 3.39 /um. An important feature of the calculations is a method of finding all the stationary solutions, even in the general case. For the three examples considered we find many stationary polarization states. A linear stability analysis shows that only two are stable and permits us to relate our calculations to additive pulse mode locking, to Casperson instabilities, and to Hopf bifurcations.
Polarization fluctuations in vertical-cavity semiconductor lasers
Physical Review A, 1998
We report, theoretically and experimentally, how polarization fluctuations in vertical-cavity semiconductor lasers are affected by optical anisotropies. We develop a spin-eliminated ͑class A͒ description of laser polarization and show how the various model parameters can be extracted from the experimental data. In practice, the linear anisotropies are often much stronger than the nonlinear anisotropies, so that the polarization modes defined by the linear anisotropies form a useful basis. For this case we derive a one-dimensional model for polarization noise, with simple expressions for the relative strength of the polarization fluctuations and the rate of polarization switches. For the other, more extreme, case where the nonlinear anisotropies are as strong ͑or even stronger͒ than the linear anisotropies, the spin-eliminated description remains valid. However, in this case the concept of polarization modes is shown to lose its meaning, as a strong four-wave-mixing peak appears in the optical spectrum and polarization fluctuations become highly nonuniform. ͓S1050-2947͑98͒06311-2͔
Lyapunov-potential description for laser dynamics
Physical Review A, 1999
We describe the dynamical behavior of both class A and class B lasers in terms of a Lyapunov potential. For class A lasers we use the potential to analyze both deterministic and stochastic dynamics. In the stochastic case it is found that the phase of the electric field drifts with time in the steady state.