Vertical-cavity surface-emitting laser with a liquid crystal external cavity

We have developed a technology to integrate a thin layer of liquid crystal (LC) on top of a Vertical-Cavity Surface-Emitting Laser (VCSEL). Based on this technology, we demonstrate VCSELs with a chiral liquid crystal (CLC) layer, which acts as a tuneable mirror. The reflection properties of the CLC layer are controlled by temperature. Next we demonstrate VCSEL devices with tuneable external cavity using a nematic LC layer incorporated with an additional dielectric mirror (SiO2/Ta2O5). The VCSEL and the LC layer can be electrically driven independently and the optical length in the external cavity can be tuned by the applied voltage on the LC layer. In both configurations we show that the emission properties of the VCSEL can be changed, in terms of emission wavelength, polarization state and/or lasing threshold

Irregular pulsating polarization dynamics in gain-switched vertical-cavity surface-emitting lasers

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceIn this paper, we report on experimental and theoretical investigation on the nonlinear dynamics of the two orthogonal linearly polarized fundamental transverse modes of verticalcavity surface-emitting lasers (VCSELs) under sinusoidal current modulation. Irregular pulses of the power of individual polarizations are measured with a period equal to twice the modulation period. In contrast with individual polarizations, total power displays regular pulsing at twice the modulation period. The variability of pulse streams is characterized by using residence times distributions. We show that the residence time distributions for individual linear polarizations display an exponential decay for large values of that time. Those results are well reproduced by using a theoretical model that includes spontaneous emission fluctuations. However the previous qualitative features remain even in the absence of spontaneous emission noise. Our results therefore suggest that the irregular polarization dynamics have a deterministic origin and can be defined as deterministic chaos

Bifurcation structure of cavity soliton dynamics in a VCSEL with saturable absorber and time-delayed feedback

We consider a wide-aperture surface-emitting laser with a saturable absorber section subjected to time-delayed feedback. We adopt the mean-field approach assuming a single longitudinal mode operation of the solitary VCSEL. We investigate cavity soliton dynamics under the effect of time- delayed feedback in a self-imaging configuration where diffraction in the external cavity is negligible. Using bifurcation analysis, direct numerical simulations and numerical path continuation methods, we identify the possible bifurcations and map them in a plane of feedback parameters. We show that for both the homogeneous and localized stationary lasing solutions in one spatial dimension the time-delayed feedback induces complex spatiotemporal dynamics, in particular a period doubling route to chaos, quasiperiodic oscillations and multistability of the stationary solutions

Stabilization of localized structures by inhomogeneous injection in Kerr resonators

We consider the formation of temporal localized structures or Kerr comb generation in a microresonator with inhomogeneities. We show that the introduction of even a small inhomogeneity in the injected beam widens the stability region of localized solutions. The homoclinic snaking bifurcation associated with the formation of localized structures and clusters of them with decaying oscillatory tails is constructed. Furthermore, the inhomogeneity allows not only to control the position of localized solutions, but strongly affects their stability domains. In particular, a new stability domain of a single peak localized structure appears outside of the region of multistability between multiple peaks of localized states. We identify a regime of larger detuning, where localized structures do not exhibit a snaking behavior. In this regime, the effect of inhomogeneities on localized solutions is far more complex: they can act either attracting or repelling. We identify the pitchfork bifurcation responsible for this transition. Finally, we use a potential well approach to determine the force exerted by the inhomogeneity and summarize with a full analysis of the parameter regime where localized structures and therefore Kerr comb generation exist and analyze how this regime changes in the presence of an inhomogeneity

Transverse Mode Switching and Locking in Vertical-Cavity Surface-Emitting Lasers Subject to Orthogonal Optical injection

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.In this paper, we report on theoretical and experimental investigation on polarization and transverse mode behavior of vertical-cavity surface-emitting lasers (VCSELs) under orthogonal optical injection as a function of the injection strength and of the detuning between the injection frequency and the free-running frequency of the solitary laser. As the injection strength increases the VCSEL switches to the master laser polarization. We find that the injection power necessary to obtain such polarization switching is minimum at two different values of the frequency detuning: the first one corresponds to the frequency splitting between the two linearly polarized fundamental transverse modes, and the second one appears at a larger positive frequency detuning, close to the frequency difference between the first-order and the fundamental transverse modes of the solitary VCSEL. We show theoretically that both the depth and the frequency corresponding to the second minimum increase when the relative losses between the two transverse modes decrease. Bistability of the polarization switching is obtained for the whole frequency detuning range. Such a bistability is found for the fundamental mode only or for both transverse modes, depending on the value of the detuning. The theoretical and experimental optical spectra are in good agreement showing that the first-order transverse mode appears locked to the external injection

Delay-differential-equation modeling of mode-locked vertical-external-cavity surface-emitting lasers in different cavity configurations

A simple, versatile model for the dynamics of electrically and optically pumped vertical-external-cavity surface-emitting lasers mode locked by semiconductor saturable absorber mirror is presented. The difference between the laser operation in the linear and folded cavity, as well as the potential for colliding pulse operation, are studied

Spontaneous motion of cavity solitons induced by a delayed feedback

We consider a broad area Vertical-Cavity Surface Emitting Laser (VCSEL) operating below the lasing threshold and subject to optical injection and time-delayed feedback. We derive a generalized delayed Swift-Hohenberg equation for the VCSEL system which is valid close to the nascent optical bistability. We first characterize the stationary cavity solitons by constructing their snaking bifurcation diagram and by showing clustering behavior within the pinning region of parameters. Then we show that the delayed feedback induces a spontaneous motion of two-dimensional cavity solitons in an arbitrary direction in the transverse plane. We characterize moving cavity solitons by estimating their threshold and calculating their velocity. Numerical 2D solutions of the governing semiconductor laser equations are in close agreement with those obtained from the delayed generalized Swift- Hohenberg equation

Effect of temperature on polarization switching in long-wavelength VCSELs

Trabajo presentado al Vertical-Cavity Surface-Emitting Lasers XIX, celebrado en San Francisco, California (US) del 11 al 12 de febrero de 2015.We have measured the effect of the temperature on the polarization-resolved characteristics of a 1550-nm singletransverse mode vertical-cavity surface-emitting laser (VCSEL). Two double polarization switchings (PS) are observed. For low temperatures a PS from longer to shorter wavelengths (Type II PS) followed by the opposite PS (Type I) is observed. For higher temperatures Type I followed by Type II PS are measured. A simple expression relating the spin flip rateto the dichroism, differential gain, threshold current and PS current is derived. With this expression the dependence of the spin-flip rate on the temperature is obtained.This work has been funded by the Ministerio de Economía y Competitividad, Spain under project TEC2012-38864-C03-03 and cofinanced by FEDER funds. A. Quirce acknowledges FWO for her Post Doc fellowship and H. Thienpont and K. Panajotov are grateful to the Methusalem foundation for financial support.Peer reviewe