Efficient FDTD Simulation of Active Photonic Devices With Multiple Temporal Resolutions

A computational method to reduce computational time for finite-difference time-domain simulations of active photonic devices by using different temporal resolutions for the update of Maxwell's equations and active-medium (AM) equations are presented. A larger temporal resolution for the update of AM equations is used due to their slower evolution in comparison to the electromagnetic fields. Slow varying envelope approximation in the carrier rate equations are avoided. The method is easy to implement and is validated through numerical examples of semiconductor microdisk lasers. A speed enhancement of between two to threefold can be obtained without loss in accuracy.