The effects of spin-orbit (SO) coupling arising from the confinement
potential in single and two vertically-coupled quantum dots have been
investigated. Our work indicates that a dot containing a single electron shows
the lifting of the degeneracy of dipole-allowed transitions at B=0 due to the
SO coupling which disappears for a dot containing two electrons. For coupled
dots with one electron in each dot, the optical spectra is not affected by the
coupling and is the same as the dot containing one electron. However, for the
case of two coupled dots where one partner dot has two interacting electrons
while the other dot has only one electron, a remarkable effect is observed
where the oscillator strength of two out of four dipole-allowed transition
lines disappears as the distance between the dots is decreased