Accurate sensitivity analysis of photonic devices exploiting the finite-difference time-domain cavity adjoint...

Area of Science:

• Photonics
• Computational electromagnetics
• Device simulation

Background:

• Sensitivity analysis is crucial for optimizing photonic device design.
• Traditional methods like finite difference approximation are computationally expensive.

Purpose of the Study:

• To introduce and validate the central adjoint variable method (CAVM) for sensitivity analysis in photonic devices.
• To demonstrate the efficiency and accuracy of the FDTD-CAVM technique.

Main Methods:

• Application of the central adjoint variable method (CAVM) to finite-difference time-domain (FDTD) simulations.
• Performing a single FDTD simulation to extract sensitivities for all design parameters.
• Derivation of cost-free sensitivities for power reflectivity.

Main Results:

• The FDTD-CAVM technique accurately determines sensitivities of device responses to design parameters.
• Sensitivities are obtained with only one additional FDTD simulation, regardless of parameter count.
• Cost-free sensitivities for power reflectivity were successfully derived.
• CAVM-derived sensitivities showed excellent agreement with finite difference approximation results.

Conclusions:

• The FDTD-CAVM method offers an efficient and accurate alternative for photonic device sensitivity analysis.
• This technique significantly reduces the computational cost associated with design optimization.
• The method is broadly applicable for analyzing sensitivities of various photonic device responses.