Transformation-optics modeling of 3D-printed freeform waveguides

Area of Science:

• Photonics
• Computational Electromagnetics
• Materials Science

Background:

• Planar photonic integrated circuits (PICs) can be enhanced with 3D-printed freeform waveguides using multi-photon lithography.
• Modeling these freeform waveguides with traditional solvers is computationally intensive due to large simulation volumes.
• Existing methods lack efficiency for optimizing complex, curved waveguide designs.

Purpose of the Study:

• To develop a computationally efficient method for designing and optimizing 3D freeform waveguides for PICs.
• To reduce the computational burden associated with modeling complex waveguide geometries.
• To enable faster design cycles for integrated photonic devices.

Main Methods:

• A solver-independent transformation optics (TO) technique is presented.
• Freeform waveguides with curved trajectories are transformed into equivalent straight waveguides with modified material properties.
• This transformation allows fitting the structures into smaller computational volumes for efficient simulation.

Main Results:

• The TO-based technique significantly reduces simulation time for 3D freeform waveguides by a factor of 3-6.
• The method demonstrates potential for further computational efficiency improvements.
• Fabricated and tested waveguides show good agreement between simulated and measured transmission at 1550 nm.

Conclusions:

• The proposed transformation optics method offers a viable and efficient approach for modeling 3D freeform waveguides.
• This technique enhances the design and optimization process for advanced photonic integrated circuits.
• Experimental validation confirms the accuracy and practical applicability of the computational method.