Coupled-zigzag-wave theory for guided waves in slab waveguide arrays

The guided wave in a slab waveguide array is treated as a set of coupled zigzag waves that propagate in the individual waveguides. This treatment leads to an exact dispersion relation for the TE and TM modes of the array, which can be expressed in a recurrence form and is easy to evaluate. Approximations for weakly coupled waveguides are discussed and compared with the coupled-mode theory. It is shown that the present theory can be cast in a form that closely resembles the coupled-mode theory.<
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