The fast quasi-adiabatic dynamics (FAQUAD) protocol has proven to be an effective approach to provide shortcuts to adiabatic light evolution in optical waveguides, resulting in short and robust devices. However, the FAQUAD approach of homogeneously distributing device adiabaticity only works for a single mode (polarization, wavelength, or spatial mode group) system. We propose an adiabaticity engineering approach to redistribute the adiabaticity of optical waveguides in multi-mode systems. By engineering the adiabaticity distribution using a single control parameter, we obtain shortcuts to adiabaticity in optical waveguides for multi-mode systems. The concept is applied to the design of a compact polarization-independent adiabatic 3-dB coupler on silicon.

中文翻译：

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光波导的绝热工程

快速准绝热动力学（FAQUAD）协议已被证明是一种有效的方法，可为光波导中的绝热光演化提供捷径，从而使设备短而坚固。但是，均匀分布设备绝热的FAQUAD方法仅适用于单模（偏振，波长或空间模群）系统。我们提出了一种绝热工程方法来重新分布多模系统中光波导的绝热性。通过使用单个控制参数设计绝热分布，我们获得了多模系统光波导中绝热的捷径。该概念适用于硅上紧凑的偏振无关绝热3dB耦合器的设计。