22 research outputs found
Excitability of a DFB laser with short external cavity
We discuss some aspects of the excitability in a semiconductor laser with short external cavity. It is demonstrated both theoretically and experimentally how a two-section semiconductor laser consisting of a DFB section and an integrated passive phase tuning section performs an excitable response to optical injection. A mode analysis of the model equations allows to understand and explain the origin of the excitability
On the Dynamics of Single Mode Lasers with Passive Dispersive Reflector
For passive dispersive reflector (PDR) lasers we investigate a single mode model containing two functions characterizing the influence of the PDR. We study numerically the effect of the shape of these functions on the existence and robustness of self-pulsations. The possibility of tuning the frequency and modulation depth of the self-pulsations has been demonstrated
Space Charge Transfer in Hybrid Inorganic/Organic Systems
We discuss density functional theory calculations of hybrid inorganic/organic
systems (HIOS) that explicitly include the global effects of doping (i.e.
position of the Fermi level) and the formation of a space-charge layer. For the
example of tetrafluoro-tetracyanoquinodimethane (F4TCNQ) on the
ZnO(000) surface we show that the adsorption energy and electron
transfer depend strongly on the ZnO doping. The associated work function
changes are large, for which the formation of space-charge layers is the main
driving force. The prominent doping effects are expected to be quite general
for charge-transfer interfaces in HIOS and important for device design
Nonlinear dynamics of semiconductor lasers with active optical feedback
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 multi-section device of sub-mm total length provides access to the short-cavity regime. By introducing an amplifier section as novel feature, phase and strength of the feedback can be separately tuned. In this way, the number of modes involved in the laser action can be adjusted. We predict and observe specific dynamical scenarios. Bifurcations mediate various transitions in the device output, from single-mode steady-state to self-pulsation and between different kinds of self-pulsations, reaching eventually chaotic behavior in the multi-mode limit
Semiconductor quantum bits
Semiconductor nanostructures provide simultaneously various ways of qubit implementation as well as a way to transfer quantum information from these stationary qubits to flying qubits (photons). This book highlights the qubit implementations in semiconductors and provides an overview of this field
Synchronization Properties of Two Coupled Multisection Semiconductor Lasers Emitting Chaotic Light
3 pages.-- Final full-text version of the paper available at: http://dx.doi.org/10.1109/LPT.2006.883179.We present numerical simulations describing the
dynamics of two multisection semiconductor lasers emitting in a chaotic regime coupled in a master-slave configuration. By changing the current of the passive section of the master laser we observe a change in the maximum correlation between the outputs of the two systems. These devices are promising candidates for on/off phase shift keying encryption.This work is supported by the MEC Acciones Integradas Project HA2005-0051 and MCyT
Spain and Feder, by Project TEC-2005- 07799-02-01/MIC and Project FIS2004-00953, by the EC Project PICASSO IST-2005-34551, and by DAAD Projekt D/05/50619. The work of M. Radziunas was supported by the DFG Research Center Matheon
Excitability of a DFB laser with short external cavity
We discuss some aspects of the excitability in a semiconductor laser with short external cavity. It is demonstrated both theoretically and experimentally how a two-section semiconductor laser consisting of a DFB section and an integrated passive phase tuning section performs an excitable response to optical injection. A mode analysis of the model equations allows to understand and explain the origin of the excitability