There are two main approaches in the investigation of devices and circuits behavior, a physical-based one and a model-based one. The first approach tries to simulate the real physical behavior by solving the equations describing the physical phenomena and it is used by electromagnetic simulators, which are rigorous but very slow and memory consuming. The second approach tries to simulate devices and circuits behavior by modeling the phenomena behind the physical mechanisms through equations that “behave-like” the real word. It is used by circuit simulators and gives accurate results only if the chosen model is correct but it is many orders of magnitude faster and less memory consuming than the first one.

Aspic is a circuit simulator that exploit fast simulation techniques in the frequency domain to perform accurate simulations of the behavior of arbitrary large and complex optical circuits, avoiding the difficulties that standard electromagnetic simulators face when used to simulate large structures.