3,909 research outputs found
Phases dynamics in VCSELs with delayed optical feedback and cross re-injection
We study theoretically the non linear polarization dynamics of
Vertical-Cavity Surface-Emitting Lasers in the presence of an external cavity
providing delayed optical feedback and cross polarization re-injection. We show
that far from the laser threshold, the dynamics remains confined close to the
equatorial plane of a Stokes sphere of a given radius and we reduce the
dynamics to a dynamical system composed of two phases: the orientation phase of
the quasi-linear polarization and the optical phase of the field. We explore
the complex modal structure given by the double feedback configuration and
recovers as particular cases the Lang-Kobayashi modes and the modes founds by
Giudici et al. [1]. We also re-interpret the square waves switching dynamics as
phase kinks.Comment: 10 pages, 7 figures, pre-submission to Phys. Rev.
Vectorial dissipative solitons in vertical-cavity surface-emitting Lasers with delays
We show that the nonlinear polarization dynamics of a vertical-cavity
surface-emitting laser placed into an external cavity leads to the formation of
temporal vectorial dissipative solitons. These solitons arise as cycles in the
polarization orientation, leaving the total intensity constant. When the cavity
round-trip is much longer than their duration, several independent solitons as
well as bound states (molecules) may be hosted in the cavity. All these
solutions coexist together and with the background solution, i.e. the solution
with zero soliton. The theoretical proof of localization is given by the
analysis of the Floquet exponents. Finally, we reduce the dynamics to a single
delayed equation for the polarization orientation allowing interpreting the
vectorial solitons as polarization kinks.Comment: quasi final resubmission version, 12 pages, 9 figure
Fundamentals and applications of spatial dissipative solitons in photonic devices : [Chapter 6]
We review the properties of optical spatial dissipative solitons (SDS). These are stable, self‐localized optical excitations sitting on a uniform, or quasi‐uniform, background in a dissipative environment like a nonlinear optical cavity. Indeed, in optics they are often termed “cavity solitons.” We discuss their dynamics and interactions in both ideal and imperfect systems, making comparison with experiments. SDS in lasers offer important advantages for applications. We review candidate schemes and the tremendous recent progress in semiconductor‐based cavity soliton lasers. We examine SDS in periodic structures, and we show how SDS can be quantitatively related to the locking of fronts. We conclude with an assessment of potential applications of SDS in photonics, arguing that best use of their particular features is made by exploiting their mobility, for example in all‐optical delay lines
Abrupt turn-on and hysteresis in a VCSEL with frequency-selective optical feedback
The emission characteristics of a vertical-cavity surface-emitting laser (VCSEL) operated in a single-transverse mode and coupled to an external cavity with a diffraction grating as a frequency-selective element are analyzed experimentally, numerically and analytically. The experiments yield a rather abrupt turn-on of the VCSEL to a high-amplitude emission state and hysteresis phenomena. The experimental results are explained by numerical simulations and analytical calculations demonstrating the possibility of bistability between lasing and non-lasing states close to threshold. Hence, the scheme might be useful in all-optical photonic switching applications. A detailed bifurcation analysis near threshold is given by superimposing the numerical results with analytical steady-state curves. The mode selection and switching behavior obtained in the simulations can be interpreted from the point of view of the preference of states with the minimal total losses
Polarization dynamics in vertical-cavity surface emitting lasers
Experiments and their interpretation on polarization dynamics and polarization switching in vertical-cavity surface-emitting lasers operated in the fundamental transverse mode regime are reviewed. Important observations are switching events to a mode with the lower unsaturated gain and the existence of elliptically polarized dynamical transition states after the destabilization of the low-frequency polarization mode. The observations demonstrate the need to consider explicitly the phase properties of the optical field as well as nonlinear effects affecting polarization selection above threshold. Good qualitative agreement is found with a model which takes into account the spin degrees of freedom of the light field as well as of the carriers (`spin-flip model'), if the spin-flip rate is taken to be some tens of ~s. This constitutes a strong -- though indirect -- indication that spin dependent processes are important in polarization selection in the devices investigated
External wavelength stabilization of grating coupled surface emitting lasers and applications
In this dissertation, we explore a semiconductor optical device configuration based on non-resonant diffraction grating coupler. These devices are coupled with monolithic and external wavelength selection elements to form the resonant cavity lasing at ~980nm. Different configurations of these external and monolithic lasers in one-dimensional (1-D) and two-dimensional (2-D) array were fabricated and experimentally studied under quasi-continuous wave (QCW) and pulsed pump current conditions. The lasers are also utilized in blue light generation through nonlinear second harmonic generation (SHG). Diffractive micro-optical beam shaping optics were designed and fabricated for a compact multi-wavelength high peak power blue light source
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