467 research outputs found
Semiconductor Laser Dynamics
No full textThis is a collection of 18 papers, two of which are reviews and seven are invited feature papers, that together form the Photonics Special Issue “Semiconductor Laser Dynamics: Fundamentals and Applications”, published in 2020. This collection is edited by Daan Lenstra, an internationally recognized specialist in the field for 40 years
Multi-longitudinal-mode dynamics in twin-stripe lasers
No full textSimulations for two laterally coupled Fabry-Perot type semiconductor lasers are presented. We show a threshold reduction effect and synchronization of the longitudinal modes in case of asymmetric pumping. For symmetric pumping 50% above threshold we find chaotic oscillations with frequencies well exceeding the single-stripe relaxation oscillation frequencies
Phase-shift stabilization of 500 Gbit/s ultra-short optical pulses in a semiconductor optical amplifier by Manchester encoding
No full textWe present simulation results of the time-evolution of a pulse-train consisting of 200 fs optical pulses at an effective bit-rate of 500 Gbit/s in a semiconductor optical amplifier (SOA). The SOA slow recovery could lead to pattern effects in the output pulses. We show that the output power of the amplified data pulses can be stabilized when Manchester encoding is used. The simulation results show that this technique is suitable for applications in practical ultra-fast switching device operation
Twin photons from small quantum dots
No full textDue to the large energy splitting of the single-electron levels in a small quantum dot, only one single electron level and one single hole level can be made resonant with the levels in the conduction band and valence band. This results in a closed system with nine distinct levels, which are split by the Coulomb interactions. We show that flat and tall cylindrically symmetric dots have level schemes with different selection rules. In both cases entangled photon pairs can be efficiently produced
Twin photons from small quantum dots
No full textDue to the large energy splitting of the single-electron levels in a small quantum dot, only one single electron level and one single hole level can be made resonant with the levels in the conduction band and valence band. This results in a closed system with nine distinct levels, which are split by the Coulomb interactions. We show that flat and tall cylindrically symmetric dots have level schemes with different selection rules. In both cases entangled photon pairs can be efficiently produced
All-optical flip-flop memory by using two coupled polarization switches
No full textAn all-optical flip-flop memory with separate set and reset inputs is presented. The flipflop is formed from two coupled polarization switches that are operated by utilizing the nonlinear polarization rotation in semiconductor optical amplifiers. The concept of the system is explained and experimental results are presented, demonstrating that a contrast ratio of over 20 dB between output states and a switching power of less than -3 dBm can be obtained. The all-optical flip-flop can be utilized in all-optical packet switches
Ultrafast refractive-index dynamics in a multi-quantum well semiconductor optical amplifier
No full textWe investigate ultrafast refractive index dynamics in a multi-quantum well InGaAsPInGaAs
semiconductor optical amplifier that is operated in the gain regime by using
pump and probe pulses that are cross-linearly polarized. We observe a phase shift of
200 degrees if the amplifier is pumped with 120 mA of current, but find that the phase
shift vanishes if the injection current is increased to 160 mA. Our results indicate a
contribution of two-photon absorption to the nonlinear phase shift that opposes the
phase shift introduced by the gain. We observe that the phase shift comes up and
disappears within a picosecond
Phase-shift stabilization of 500 Gbit/s ultra-short optical pulses in a semiconductor optical amplifier by Manchester encoding
No full textWe present simulation results of the time-evolution of a pulse-train consisting of 200 fs optical pulses at an effective bit-rate of 500 Gbit/s in a semiconductor optical amplifier (SOA). The SOA slow recovery could lead to pattern effects in the output pulses. We show that the output power of the amplified data pulses can be stabilized when Manchester encoding is used. The simulation results show that this technique is suitable for applications in practical ultra-fast switching device operation
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