Numerical Method for the Design of Compact Adiabatic Devices with Multiple Parameter Variations

Abstract

In this study, a numerical method for designing efficient adiabatic devices with multiple structural parameter variations (NAMSP) is developed. This method can be applied to a wide range of devices based on adiabatic mode evolution structures. The numerical design complexity of multiple structural parameter variations will be greatly improved compared to the case of a single parameter variation. Therefore, an efficient domain decomposition scheme was originally introduced into the NAMSP method. The proposed method can help compute compact adiabatic guided-wave shapes for these adiabatic devices with multiple structural parameter variations. Adiabatic devices with multiple structural parameter variations are used to connect different complex waveguides, which are often difficult to design using analytical methods. The design involves tapering the width of the two or more core layers at one time; however, this change in the width typically affects the mode both vertically and horizontally. Our numerical method allows the shape of the width variation for each layer that facilitates compact adiabatic mode transformation to be obtained. The efficiency of the adiabatic device that was designed using the NAMSP method considerably exceeds that obtained using a linear-shaped device. Moreover, our designed adiabatic device enables an ultra-wide operating bandwidth (spans in the wavelength from 1050 nm to 4780 nm).