Numerical modeling of coherent coupling and radiation fields in planar Y-branch interferometers

The beam-propagation method is used to study intermodal power transfer and radiation losses in slab waveguide splitters and combiners. Numerical computations demonstrate how modal power at an interferometer's recombination point exhibits an oscillatory dependence on the length of each distinct section of the structure. Recoupling of guided and unguided modes can be anticipated and adjusted so as to maximize output modal power and minimize sensitivity to transition lengths. Examples are given for systems formed from both angle bends and S bends.<
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