Mindaugas Radziunas

Learn More
An in-depth theoretical as well as experimental analysis of the nonlinear dynamics in semiconductor lasers with active optical feedback is presented. Use of a monolithically integrated multisection device of submillimeter total length provides access to the short-cavity regime. By introducing an amplifier section as a special feature, phase and strength of(More)
We investigate the longitudinal dynamics of multisection semiconductor lasers based on a model, where a hyperbolic system of partial differential equations is nonlinearly coupled with a system of ordinary differential equations. We present analytic results for that system: global existence and uniqueness of the initial-boundary value problem, and existence(More)
This paper presents the analysis of the split step solvers for multidimensional Schrödinger problems. The second-order symmetrical splitting techniques are applied. The standard operator splitting is used to split the linear diffraction and reaction/potential processes. The dimension splitting exploits the commuting property of one-dimensional discrete(More)
We report on the preparation of optical excitability in a distributed feedback semiconductor laser. The device integrates a single-mode laser and a 250 microm long passive section with cleaved facet. The phase of the light fed back from the passive section is tunable by current. The theoretical analysis shows an ultimate hop between external cavity modes(More)
We study the continuous-wave (cw) operation of a semiconductor laser subject to optical feedback from a Fabry-Perot resonator in a case where the emission is resonant to a reflection minimum of the resonator. This configuration is treated in the framework of Lang-Kobayashi equations. The nature of bifurcations and the stability of steady state solutions is(More)
We present the first demonstration of an InAs/InP Quantum Dash based single-section frequency comb generator designed for use in photonic integrated circuits (PICs). The laser cavity is closed using a specifically designed Bragg reflector without compromising the mode-locking performance of the self pulsating laser. This enables the integration of(More)
We consider theoretically the lasing properties of distributed-feedback master-oscillator power-amplifiers which are compact semiconductor laser devices capable of emitting a high brilliance beam at an optical power of several Watts. Based on a traveling wave equation model we calculate emitted optical power and spectral maps for increasing current(More)
Stripe-array diode lasers naturally operate in an anti-phase supermode. This produces a sharp double lobe far field at angles +/-alpha depending on the period of the array. In this paper a 40 emitter gain guided stripe-array laterally coupled by off-axis filtered feedback is investigated experimentally and numerically. We predict theoretically and confirm(More)
We propose and analyze a beam-shaping mechanism that in broad-area semiconductor amplifiers occurs due to spatial pump modulation on a micrometer scale. The study, performed under realistic parameters and conditions, predicts a spatial (angular) filtering of the radiation, which leads to a substantial improvement of the spatial quality of the beam during(More)
W. W. Ahmed, S. Kumar, R. Herrero, M. Botey, M. Radziunas and K. Staliunas Departament de Fisica i Enginyeria Nuclear, Universitat Politècnica de Catalunya (UPC), Colom 11, E-08222 Terrassa, Barcelona, Spain Weierstrass Institute for Applied Analysis and Stochastics, Leibniz Institute in Forschungsverbund Berlin e.V., Mohrenstrasse 39, 10117 Berlin, Germany(More)