Monte Carlo studies on the well‐width dependence of carrier capture time in graded‐index separate confinement heterostructure quantum well laser structures

The total carrier capture time and the quantum well width are both important parameters affecting the graded‐index separate confinement heterostructure (GRINSCH) quantum well laser modulation speed limit. However, discrepancies exist in the literature on the well‐width dependence of the carrier capture times. To study this phenomenon, we have developed a Monte Carlo technique to simulate carrier relaxation in GRINSCH quantum well structures. Our results show that the carrier capture time increases with the density of carrier injection. Furthermore, depending on the concentration of injected carriers, the capture time will either decrease, remain the same, or increase with increases in the well width. At lasing conditions, the times are more or less independent of the well width up to 100 Å. We compare our calculations to published experiments and find good agreements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70766/2/APPLAB-63-14-1874-1.pd

Carrier dynamics and gain saturation in quantum-well lasers

A Monte Carlo technique has been developed to investigate the carrier dynamics and static gain saturation in graded-index separate confinement heterostructure quantumwell laser structures. The calculated electron relaxation times and gain compression coefficient show good agreement with published experiments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43335/1/11082_2004_Article_BF00326660.pd

Comparison of mode suppression and large signal modulation between lattice matched and strained InGaAs/AlGaAs quantum well lasers

Numerical techniques are developed to study the output spectra and to solve the coupled mode rate equations for InxGa1−xAs/Al0.3Ga0.7As quantum well lasers. The optical properties of the laser are calculated from a 4×4 k⋅p band structure which includes the effects of strain. We find that the side modes are severely suppressed in the strained laser. Large signal switching of the laser is also studied and the role of strain is identified in the device response. If the laser is switched from the off state to a state of given photon density in the lasing mode, then the strained system exhibits a faster time response. If, however, the laser is switched from the off state to a state of given total photon density, then the strained system has a slower time response.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70732/2/APPLAB-59-19-2381-1.pd

Photoluminescence and electro‐optic properties of small (25–35 nm diameter) quantum boxes

The luminescence and electro‐optic properties of buried 25–35 nm quantum boxes have been measured. The quantum boxes were defined by a combination of molecular beam epitaxial growth and regrowth, electron beam lithography, and dry etching. The photoluminescence from 35 nm boxes shows a blue shift of ∼15 meV compared to the bulk luminescence and an enhancement, taking into account the fill factor. An enhanced effective linear electro‐optic coefficient, rl, is observed for the quantum boxes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69405/2/APPLAB-62-22-2766-1.pd