Analytical approximation of the radiation confinement factor for the TE0mode of a double heterojunction laser

An analytical approximation is found for
\Gamma_{0}
, the TE
0
radiation confinement factor in symmetric heterostructures, by using a combination of its asymptotes in the limits of very thin active layers and thick active layers, respectively. The exact expression for
\Gamma_{0}
is calculated and compared to the approximation formula. It is found that for any light guiding planar double heterostructure (DH) configuration the approximation is at most -1.5 percent off with respect to the exact
\Gamma_{0}
value.