In this work we study a possibility of waveguide fabrication on the basis of active quantum wells in semiconductor lasers. The efficiency of such a waveguide for an InP structure with In0.53Ga0.47As quantum wells is demonstrated experimentally. An optically-pumped laser on this basis is realized.
A traveling wave model for a semiconductor diode laser based on quantum wells is presented as well as a comprehensive theoretical model of the lasing dynamics produced by the intensity discrimination of the nonlinear mode-coupling in a waveguide array. By leveraging a recently developed model for the detailed semiconductor gain dynamics, the temporal shaping effects of the nonlinear mode-coupling induced by the waveguide arrays can be characterized. Specifically, the enhanced nonlinear pulse shaping provided by the waveguides are capable of generating stable frequency combs wavelength of 800 nm in a GaAs device, a parameter regime not feasible for stable combline generation using a single waveguide. Extensive numerical simulations showed that stable waveform generation could be achieved and optimized by an appropriate choice of the linear waveguide coupling coefficient, quantum well depth, and the input currents to the first and second waveguides. The model provides a first demonstration that a compact, efficient and robust on-chip comb source can be produced in GaAs.
We experimentally demonstrate the existence of non dispersive solitary waves associated with a 2$pi$ phase rotation in a strongly multimode ring semiconductor laser with coherent forcing. Similarly to Bloch domain walls, such structures host a chiral charge. The numerical simulations based on a set of effective Maxwell-Bloch equations support the experimental evidence that only one sign of chiral charge is stable, which strongly affects the motion of the phase solitons. Furthermore, the reduction of the model to a modified Ginzburg Landau equation with forcing demonstrates the generality of these phenomena and exposes the impact of the lack of parity symmetry in propagative optical systems.
We report on a new design of terahertz quantum cascade laser based on a single, potential-inserted quantum well active region. The quantum well properties are engineered through single monolayer InAs inserts. The modeling is based on atomistic, spds* tight-binding calculations, and performances are compared to that of the classical three-well design. We obtain a 100% increase of the oscillator strength per unit length, while maintaining a high, nearly temperature-independent contrast between phonon-induced relaxation times of the upper and lower lasing states. The improved performances are expected to allow THz lasing at room temperature.
We study the effect of noise on the dynamics of passively mode-locked semiconductor lasers both experimentally and theoretically. A method combining analytical and numerical approaches for estimation of pulse timing jitter is proposed. We investigate how the presence of dynamical features such as wavelength bistability affects timing jitter.
A microscopic study of mode-locked pulse generation is presented for vertical external-cavity surface-emitting lasers utilizing type-II quantum well configurations. The coupled Maxwell semiconductor Bloch equations are solved numerically where the type-II carrier replenishment is modeled via suitably chosen reservoirs. Conditions for stable mode-locked pulses are identified allowing for pulses in the unit[100]{fs} range. Design strategies for type-II configurations are proposed that avoid potentially unstable pulse dynamics.