  We introduce a new version of non-linear electrodynamics which is produced by
a spontaneous symmetry breaking of Lorentz invariance induced by the non-zero
expectation value of the electromagnetic field strength. The symmetry breaking
potential is argued to effectively arise from the integration of massive gauge
bosons and fermions in an underlying fundamental theory. All possible choices
of the vacuum lead only to the remaining invariant subgroups T(2) and HOM(2).
We explore the plane wave solutions of the linearized sector of the model for
an arbitrary vacuum. They present two types of dispersion relations. One
corresponds to the case of the usual Maxwell electrodynamics with the standard
polarization properties of the fields. The other dispersion relation involves
anisotropies determined by the structure of the vacuum. The model is stable in
the small Lorentz invariance violation approximation. We have embedded our
model in the photon sector of the Standard Model Extension in order to set
bounds for our parameters. The one-way anisotropic speed of light is calculated
for a general vacuum and its isotropic component is strongly bounded by
${\tilde \delta c}/c < 2 \times 10^{-32}$. The anisotropic violation
contribution is estimated by introducing an alternative definition for the
difference of the two-way speed of light in perpendicular directions $\Delta
c$, which is also strongly bounded by ${\Delta c}/c < 10^{-32}$. Finally, we
speculate on the relation of the vacuum energy of the model with the
cosmological constant and propose a connection between the vacuum fields and
the intergalactic magnetic fields.
