Abstract

A simple design method to achieve wide flattened bandwidths in the directional coupler-type light power splitters is presented, which is applicable both to the three-and two-guide couplers. Couplers with variable differences along the guide axis in the propagation constant between the waveguides are investigated, and the optimum profiles of the variation of the propagation-constant difference are designed for desired given wavelength responses. Designed examples for the three-and two-port splitting operations in the three-guide coupler and for two-port splitting operations in the two-guide coupler are demonstrated,in which the detuning of the propagation constant is assumed to be given by the electrooptic effect in the LiNbO3 used as the substrate.

[IEEE ]

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