Quantum cascade laser especially comprising a gain region (14) formed
from several layers (20) which each comprise:
- alternating strata of a first type (26) each defining a quantum
barrier made of AlInAs and strata of a second type (28) each defining a
quantum well made of InGaAs, and
- injection barriers (22), interposed between two of the layers (20).
The layers of the gain region (
14) each constitute an active region extending
from one to the other of the injection barriers (
22) which are adjacent
to it. The strata (
26, 28) are dimensioned such that:
- each of the wells comprises, in the presence of an electric field, at
least a first upper subband, a second middle subband and a third lower subband
and that
- the probability of an electron being present in the first subband is
highest in the vicinity of one of the adjacent barriers, in the second subband
in the middle part of the region and in the third subband in the vicinity of the
other of the adjacent barriers.
