Scalable High-Precision Trimming of Photonic Resonances by Polymer Exposure to Energetic Beams

Integrated photonic circuits (PICs) have seen an explosionin interest,through to commercialization in the past decade. Most PICs rely onsharp resonances to modulate, steer, and multiplex signals. However,the spectral characteristics of high-quality resonances are highlysensitive to small variations in fabrication and material constants,which limits their applicability. Active tuning mechanisms are commonlyemployed to account for such deviations, consuming energy and occupyingvaluable chip real estate. Readily employable, accurate, and highlyscalable mechanisms to tailor the modal properties of photonic integratedcircuits are urgently required. Here, we present an elegant and powerfulsolution to achieve this in a scalable manner during the semiconductorfabrication process using existing lithography tools: by exploitingthe volume shrinkage exhibited by certain polymers to permanentlymodulate the waveguide's effective index. This technique enablesbroadband and lossless tuning with immediate applicability in wide-rangingapplications in optical computing, telecommunications, and free-spaceoptics.

Automated summary

Integrated photonic circuits (PICs) have gained significant attention and commercial success in the past decade. However, the spectral characteristics of high-quality resonances in PICs are sensitive to small variations in fabrication and material constants, limiting their applicability. In this study, we propose a scalable solution using existing lithography tools to permanently modulate the waveguide's effective index by exploiting the volume shrinkage exhibited by certain polymers during the semiconductor fabrication process. This technique enables broadband and lossless tuning, making it suitable for various applications in optical computing, telecommunications, and free-space optics.