Multi-frequency finite-difference frequency-domain algorithm for active nanophotonic device simulations

Abstract

First-principles simulation of active nanophotonic devices is indispensable to optical engineering. However, direct simulation of active devices with traditional time-domain methods have been prohibitively expensive due to the inherently large time-scale difference between optical and modulation frequencies. To overcome this challenge, we present a multi-frequency finite-difference frequency-domain algorithm that efficiently performs first-principles steady-state simulations in active devices. We validate our algorithm by simulating a modulated waveguide device and find that the result of the simulation is in excellent agreement with that of coupled mode theory, while also revealing features that are neglected in typical coupled mode theory treatments. We further demonstrate that this algorithm makes it possible to effectively simulate realistic active optical devices. Our algorithm should facilitate and expedite the design and analysis of active nanophotonic components.