The well-known a-factor is a convenient measure to describe the magnitude of the amplitude-phase coupling of semiconductor lasers. But is the a-factor really a parameter? First-principle simulations of InGaAs quantum-dot lasers and amplifiers show that in spatially extended quantum-dot laser structures, the amplitude phase coupling is far from being a constant. Our computation of the a-factor d...

This thesis presents the characterization of tunnel junctions and tunnel-junction-coupled lasers. The reverse-biased leakage current in a tunnel junction can be exploited to tunnel electrons from the valence band of one active region to the conduction band of a second active region. Thus, tunnel-junction-coupled lasers are highly efficient as they allow electrons to stimulate the emission of ph...

III Two types of III-V diode lasers have been developed for new emission wavelengths. We have obtained emission at 0.9 to 1.06 Jim nom quantum-well lasers with a strained InGaAs active layer and AlGaAs confining layers. Organometallic vapor phase epitaxy (OMVPE) was used to grow the layers on GaAs substrates. These InGaAs/AlGaAs lasers have achieved threshold current densities as low as 65 Afcm...

We track the dynamic response of GaAs quantum-well semiconductor diode lasers after injection of a femtosecond pulse, using ultrafast upconversion. The continuous-wave emission shows gain dynamics and relaxation oscillations on timescales of 1–100 ps. The recirculating femtosecond pulse evolves into an ultrafast ‘‘dark pulse’’ in the wake of subpicosecond oscillations. © 1998 American Institute...

We discuss in detail a new mechanism of nonlinearity of the light–current characteristic (LCC) in heterostructure lasers with reduced-dimensionality active regions, such as quantum wells (QWs), quantum wires (QWRs), and quantum dots (QDs). It arises from: 1) noninstantaneous carrier capture into the quantum-confined active region and 2) nonlinear (in the carrier density) recombination rate outs...

In this paper, we present the characteristics of high-performance strain-compensated MOCVD-grown 1200-nm InGaAs and 1300-nm InGaAsN quantum-well (QW) lasers using AsH3 and U-Dimethylhydrazine as the group V precursors. The design of the InGaAsN QW active region utilizes an In-content of approximately 40%, which requires only approximately 0.5% N-content to realize emission wavelengths up to 131...

| It is shown that unipolar quantum well systems have potential as sources of terahertz radiation. It is demonstrated that the electronic interactions within these systems must be manipulated in order to favour radiative emission rather than non-radiative loss. Designs are advanced for tunable emitters and optically excited terahertz lasers.