Future-Ready FDTD Skills

The finite-difference time-domain (FDTD) method is a powerful full-wave simulation tool for solving Maxwell’s equations. It is widely used in modeling the behavior of light in nanophotonic devices. In this section, we introduce the fundamental concepts behind FDTD and how to use it to simulate a wide range of phenomena in photonics. As an example, we show how to compute the scattering cross-section of a dielectric sphere and benchmark it against Mie Theory.

Designing multimode devices can be a complex task. In this session, we present the tools available in Tidy3D that facilitate this process and enable precise control over mode excitation, decomposition, and tracking in dielectric waveguides. In a real device, we show the importance of modal decomposition analysis when designing multimode photonics.

Bragg gratings are periodic structures used in various optical systems. The periodicity allows Bragg gratings to reflect specific wavelengths of light while transmitting others. The key principle behind their operation is the Bragg’s condition. This section will introduce the Bragg condition and use Tidy3D to model a distributed Bragg reflector and cavity. Then, we will apply the same principle to integrated photonics and demonstrate the design of silicon waveguide Bragg gratings.

In this session, we review the theory behind photonic crystal (PhC) slabs and some of their possible applications. As a practical Tidy3D example, we show how to compute the photonic band structure of a PhC slab and how to simulate an ultra-high-Q, small-volume PhC defect cavity that is also optimized for efficient vertical light extraction.

“Inverse design” is a technique for automated photonic device design. The process involves mathematically defining a “figure of merit” for one’s device and then using gradient-based optimization to efficiently maximize this function with respect to a large number of design parameters. In this section, we introduce the basics of inverse design, discuss its connections to other techniques in deep learning, and give practical examples of how it is used to design photonic devices in Tidy3D.