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Chow W.W., Koch S.W. Semiconductor-Laser Fundamentals (Springer 1999)(L)(T)(127s)(600dpi)_EO_.djvu |
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Size 2.1Mb Date Jun 22, 2005 |
fek (solid curve) and fhk (dashed curve) for a carrier density iV2d = 1.6 x
1012 cm, and a two-band system with effective masses, rae = O.O71mo and
mh = 0.167m0...
While the evaluation of i?(fe;', k) may be time
consuming because of these small step sizes, they need to be performed only
rarely because, except for the background dielectric constant еь, $(k',k) is
independent of most of the other parameter values...
Be-
Because of dephasing (real part of correlations), the peak gain decreases and
the gain width increases...
These pro-
processes change the quasi-equilibrium Fermi-Dirac distributions to which the
carrier probabilities are driven by the carrier-carrier scattering...
Further-
Furthermore, since
V ) i ~r • , ^0.14J
the new energy eigenstates are also eigenstates of the total angular momen-
momentum J...
Expanding |n,fe) in terms of the eigenstates at к = О,
we find
Using F.3) in F.1), multiplying the result by exp(-ifc' • r)(r\m) and inte-
integrating over the volume of the crystal, we find
As indicated in Fig...
Hence, we can now repeat
all steps of the previous sections including the additional strain terms...
ТЕ (top) and TM (bottom) dipole-transition matrix elements versus
transverse carrier momentum for 4 nm Ino.1Gao.9As/Alo.1Gao.9 As
zone center, the valence bands are mixtures of heavy and light hole states
with possibly different square-well quantum numbers...
The screening field Escr(N) is
determined by iterating F.107) and the solution to F.105) until convergence
is reached...
The z-like
state at zone center occurs only with the higher lying crystal-field split state...
However, the
resulting expression for fq becomes significantly more complicated, and the
differences in the final results are not significant for the cases that have been
tested...
In the limit of an ideal two-
dimensional well with infinitely high potential barriers the binding energy
approaches four times that of the corresponding bulk material...
The gain spectrum is dominated by the
el-hhl transition, since these bands have the highest electron and hole pop-
populations at the chosen density of TV = 8.0 x 1011 cm...
There are contributions from the Hartree-
Fock and collision effects, in addition to band filling...
For carrier densities 7V2d > 1.5 x 1012cm~2, gain is present due to the
el —> hhl transition...
The transitions are between the
one electronic state e, and the two hole states, hh and lh...
We conclude this section with a discussion on how one may estimate
the laser threshold current density...
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