Ever since the development of compact and user friendly computer-aided design (CAD) for analyzing various waveguiding structures, or photonic devices, there has been a growing need to make the methods more flexible and also more efficient than they were originally found. Pioneering works dealing with numerical methods suitable for optical circuit simulations and their complex analysis date back to 1960s. It means they are actually as old as the integrated optics itself. Although these numerical techniques have appeared to be relatively powerful they can be used to study just very basic photonic ingredients, as for example various curvilinear directional couplers and branching or combining waveguides, further the tapered waveguides, S-bends, and few others. Some more sophisticated techniques even handle multidirectional propagation of the light (e.g. ring resonator – see below). One can say that these methods must be exploited in very specific way and a user may be quite limited or restricted when using them. We are however facing more and more complex optical circuits (see  and ). As an extreme example, a user may wish to analyze a functionality of devices being set up on a six inch wafer. To investigate such a structure, it is becoming a very serious task, because the layout could consist of quite “exotic” subcomponents and their mutual combinations and/or variations in the layout on the wafer. There is definitely no complex method for such a complete analysis yet and one can also conclude, that very advanced (see below what it means) circuits are often out of even theoretical simulation possibilities of those particular methods. We should also mention the fact that some numerical approaches could be able to simulate more complex photonic circuits, but the time consumption would be practically unacceptable, at least uneconomical.
Hence, the purpose of this paper is to show a relatively efficient solution to analyze advanced photonic circuits. We will consider three principal and frequently exploited numerical approaches in the following. These methods are good enough to simulate the particular basic optical ingredients. By comparing them, we will point out their advantages and disadvantages. This should directly lead to the new proposed solution when the nontrivial circuits are considered. We will be concerning with an efficient connection among these methods. Finally, the presented simulation approach of the advanced circuits will be entirely performed by a proper combination of the Optiwave Corporation products.