Abstract-This paper presents an overview of integrated optics outline of the modal propagation analysis (MPA), which will be used later to describe image formation by general and restricted multimode interference (Sections IV and V, we conclude by comparing the properties of MMI devices with those of more conventional routing and coupling devices.

Abstract-The self-imaging property of a homogeneous multimoded planar optical waveguide has been applied in the design of passive planar monomode optical couplers based on multimode interference (MMI). Based on these designs, 3 dB and cross couplers were fabricated in Si02/A120~/Si02 channel waveguides on Si substrates. Theoretical predictions and experimental results at 1.52-pm wavelength are presented which demonstrate that MMI couplers offer high performance: on-chip excess loss better than 0.5 dB, high reproducibility, low polarization dependence and small device size.

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