We have studied the optical oscillation and tunneling of light waves in optical waveguide ladders (OWLs) formed by two coupled planar optical waveguide arrays. For the band structure, a midzone gap is formed owing to band hybridization, and its wavenumber position can be tuned throughout the whole Brillouin zone, which is different from the Bragg gap. By imposing a gradient in the propagation constant in each array, Bloch–Zener oscillation (BZO) is realized with Zener tunneling between the bands occurring at the midzone, which is contrary to the common BZO with tunneling at the center or edge of the Brillouin zone. The occurrence of BZO is demonstrated by using the field-evolution analysis. The tunable hybridization at the midzone enhances the tunability of BZO in the OWLs. This Letter may offer new insights into the coherent phenomena in optical lattices.
© 2010 Optical Society of America
Original Manuscript: August 6, 2010
Revised Manuscript: October 14, 2010
Manuscript Accepted: October 15, 2010
Published: November 17, 2010
Ming Jie Zheng, Gang Wang, and Kin Wah Yu, "Tunable hybridization at midzone and anomalous Bloch–Zener oscillations in optical waveguide ladders," Opt. Lett. 35, 3865-3867 (2010)