Design and optimization of an inverse-designed mid-infrared 1​×6 coarse wavelength-division multiplexer

Inverse design methods have been demonstrated significant advantages in reducing photonic device footprints and enabling highly compact device architectures. However, when applied to wavelength-division multiplexers, inverse-design approaches still face several limitations, including relatively high insertion loss and a limited number of wavelength channels.

In this work, an inverse-design approach is employed to develop a low-loss coarse wavelength-division multiplexer. The proposed device is implemented on a silicon-on-insulator platform and operates in the mid-infrared spectral regions. It supports six wavelength channels within an ultra-compact footprint of approximately 13.5×7.2 µm².