Segmented design and control in contra-directional coupler for large bandwidth tunability

We propose a novel design and control mechanism to achieve a widely tunable add-drop filtering element based on silicon photonic Grating-Assisted Contra-Directional Couplers. The proposed device has been simulated considering integration on the silicon photonics platform, allowing for wide deployment and cost-effective implementation as an integrated building block for different filtering/switching applications (e.g., multiplexers and demultiplexers). The segmented design and optimization of the coupler have been shown to enable a large drop bandwidth tunability while keeping a constant central wavelength, avoiding channel drifts. This add-drop element can be envisioned for flex-band wavelength-division multiplexing (WDM) applications as a component of wavelength-selective switches (WSS) or other switching devices.