  We have studied the propagation and Zener tunneling of light in the binary
parabolic optical waveguide array (BPOWA), which consists of two evanescently
coupled dissimilar optical waveguides. Due to Bragg reflections, BPOWA attains
two minibands separated by a minigap at the zone boundary. Various coherent
superpositions of optical oscillations and Zener tunneling occur for different
parameters on the phase diagram. In particular, Bloch-Zener oscillation and a
different type of Bloch-dipole-Zener oscillation are obtained by the
field-evolution analysis. The results may have potential applications in
optical splitting and waveguiding devices and shed light on the coherent
phenomena in optical lattices.
