In this paper, we theoretically analyze the loss and branching ratio of multimode optical branching waveguides by using a ray tracing method to obtain less mode-dependent branching characteristics. First, a 2 × 2 optical mixing and branching waveguide with a step-index profile are considered. It is found that an optimum length to achieve a low loss and stable branching ratio exists. Second, a waveguide with mode scrambler is investigated. By sacrificing some amount of insertion loss, the mode dependence can be minimized.
© 1985 Optical Society of America
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