  Combination of two basic types of synchronization, anticipated and
isochronous synchronization, is investigated numerically in coupled
semiconductor lasers. Due to the combination, a synchronization of good quality
can be obtained. We study the dependence of the lag time between two lasers and
the synchronization quality on the converse coupling retardation time
$\tau_{c21}$. When $\tau_{c21}$ is close to the difference of external cavity
round trip time $\tau$ and coupling retardation time $\tau_{c12}$, the
combination of anticipated and isochronous synchronization may produce a better
synchronization, with a lag time proportional to $\tau_{c21}$. When
$\tau_{c21}$ is largely different from $\tau-\tau_{c12}$, the combination is
noneffective and even negative in some cases, with a lag time independent of
$\tau_{c21}$.
