Subwavelength-Grating-Based 4-Channel Add-Drop Multiplexers in Silicon Photonics

We demonstrate a compact silicon photonic 4-channel optical add-drop wavelength multiplexer enabled by subwavelength-grating-based contra-directional couplers. Pass-bands of the device show on-chip insertion losses below 1.3 dB with wide 3 dB bandwidth of ∼ 6.7 nm suitable for coarse wavelength division multiplexing (CWDM) in short-reach optical interconnect applications.