  In this paper, we analyze the formation and dynamical properties of discrete
light bullets (dLBs) in an array of passively mode-locked lasers coupled via
evanescent fields in a ring geometry. Using a generic model based upon a system
of nearest-neighbor coupled Haus master equations we show numerically the
existence of dLBs for different coupling strengths. In order to reduce the
complexity of the analysis, we approximate the full problem by a reduced set of
discrete equations governing the dynamics of the transverse profile of the
dLBs. This effective theory allows us to perform a detailed bifurcation
analysis via path-continuation methods. In particular, we show the existence of
multistable branches of discrete localized states (dLSs), corresponding to
different number of active elements in the array. These branches are either
independent of each other or are organized into a snaking bifurcation diagram
where the width of the dLS grows via a process of successive increase and
decrease of the gain. Mechanisms are revealed by which the snaking branches can
be created and destroyed as a second parameter, e.g., the linewidth enhancement
factor or the coupling strength are varied. For increasing couplings, the
existence of moving bright and dark dLSs is also demonstrated.
