Bending the axis of an optical directional coupler can result in phase mismatch between the evanescently coupled waveguides. Using a quadratic bending profile, we realize the phase mismatch with a sign flip scheme for robust light coupling between the waveguides. We derive an analytical solution for the coupling scheme and show its robustness against parameter variations. Beam propagation method solution of the scalar wave equation verifies the two-level analysis and the device robustness.

中文翻译：

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二次弯曲定向耦合器中的稳健光耦合

弯曲光定向耦合器的轴可能会导致the逝耦合波导之间的相位不匹配。使用二次弯曲轮廓，我们通过符号翻转方案实现了相位失配，从而在波导之间实现了稳健的光耦合。我们导出了耦合方案的解析解，并显示了其对参数变化的鲁棒性。标量波动方程的光束传播方法解决方案验证了两级分析和设备的鲁棒性。