What is adjoint simulation?

Date	Category
2023-12-21 18:38:55	Inverse Design

The adjoint plugin allows users to take derivatives of arbitrary functions involving Tidy3D simulations through the use of the “adjoint method”. The advantage of the adjoint method is that the gradients can be computed using only two FDTD simulations, the forward and the adjoint one, independent of the number of parameters. This makes it possible to do gradient-based optimization or sensitivity analysis of devices with enormous numbers of parameters with minimal computational overhead.

We highly recommend watching the Inverse Design lectures if you are new to the adjoint method. You can also go through this tutorial for an introduction to the basic concepts related to automatic differentiation and adjoint optimization.