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Author: Bandelow, Uwe × Author: Vladimirov, Andrei × End date: 2019 × Start date: 2019 × Type: Text ×

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Now showing 1 - 4 of 4
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    A model equation for ultrashort optical pulses
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2008) Amiranashvili, Shalva; Vladimirov, Andrei; Bandelow, Uwe
    The nonlinear Schrödinger equation based on the Taylor approximation of the material dispersion can become invalid for ultrashort and few-cycle optical pulses. Instead, we use a rational fit to the dispersion function such that the resonances are naturally accounted for. This approach allows us to derive a simple non-envelope model for short pulses propagating in one spatial dimension. This model is further investigated numerically and analytically.
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    A model for mode-locking in quantum dot lasers
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2006) Viktorov, Evgeny; Mandel, Paul; Vladimirov, Andrei; Bandelow, Uwe
    We propose a model for passive mode-locking in quantum dot laser and report on specific dynamical properties of the regime which is characterized by a fast gain recovery. No Q-switching instability has been found accompanying the mode-locking. Bistability can occur between the mode-locking regime and zero intensity steady state.
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    Rotational symmetry breaking in small-area circular vertical cavity surface emitting lasers
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2010) Babushkin, Ihar; Bandelow, Uwe; Vladimirov, Andrei
    We investigate theoretically the dynamics of three low-order transverse modes in a small-area vertical cavity surface emitting laser. We demonstrate the breaking of axial symmetry of the transverse field distribution in such a device. In particular, we show that if the linewidth enhancement factor is sufficiently large dynamical regimes with broken axial symmetry can exist up to very high diffusion coefficients 10 um^2/ns.
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    Dynamical regimes in a monolithic passively mode-locked quantum dot laser
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2010) Vladimirov, Andrei; Bandelow, Uwe; Fiol, Gerrit; Arsenijevi´c, Dejan; Kleinert, Moritz; Bimberg, Dieter; Pimenov, Alexander; Rachinskii, Dmitrii
    Operation regimes of a two section monolithic quantum dot (QD) mode-locked laser are studied experimentally and theoretically, using a model that takes into account carrier exchange between QD ground state and 2D reservoir of a QD-in-a-well structure, and experimentally. It is shown analytically and numerically that, when the absorber section is long enough, the laser exhibits bistability between laser off state and different mode-locking regimes. The Q-switching instability leading to slow modulation of the mode-locked pulse peak intensity is completely eliminated in this case. When, on the contrary, the absorber length is rather short, in addition to usual Q-switched mode-locking, pure Q-switching regimes are predicted theoretically and observed experimentally.