Abstract

Directional couplers with crossed Δβ electrodes¹ remain widely used due to their ability to achieve good crosstalk levels. Recently several authors have discussed crosstalk issues in these devices due either to limitations of coupled mode theory itself² or due to effects of the input and output transition (branching) structures^3,4. Findakly and Leonberger⁴ have noted that bar states achieved with reverse phase mismatch cannot achieve zero crosstalk due to the mode coupling that occurs in the transition structures.

© 1988 Optical Society of America