Side-lobe reduction by cascading Bragg grating filters on a Si-photonic chip

Bragg-grating based cavities and coupler designs present opportunities for flexible allocation of bandwidth and spectrum in silicon photonic devices. Integrated silicon photonic devices are moving toward mainstream, mass adoption, leading to the need for compact Bragg grating based designs. In this work we present a design and experimental validation of a cascaded contra-directional Bragg-grating coupler with a measured main lobe to side-lobe contrast of 12.93 dB. This level of performance is achieved in a more compact size as compared to conventional apodized gratings, and a similar design philosophy can be used to improve side-lobe reduction in grating-based mirror design for on-chip lasers and other cavity-based designs as well. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Bragg-grating based cavities and coupler designs provide opportunities for flexible allocation of bandwidth and spectrum in silicon photonic devices. This work presents a design and experimental validation of a cascaded contra-directional Bragg-grating coupler with improved performance compared to conventional apodized gratings.