  Lorentz and CPT violation in the photon sector with the operators of
arbitrary mass dimension has been proposed in the context of Standard-Model
Extension. The CPT-odd subset of this enlarged model is investigated from a
quantum-field theoretical point of view. The generic forms of dispersion
relations, polarization vectors and the propagators are obtained for this
special subset. Particularly, the general vacuum-orthogonal model is analyzed
and it is demonstrated that the vacuum orthogonal model remains vacuum
orthogonal at all orders. Although the model has birefringent solutions, they
are shown to be spurious. Furthermore, the relevant polarization vectors are
shown to be conventional. Leading order model is explicitly analyzed and it is
demonstrated that there exists a nontrivial coefficient space satisfying above
properties.
