OptiSPICE is definitely geared towards circuit level design, which include optical component and interconnects (waveguides, micro rings). As for material design in some ways it might, but I think from your description you really want to declare the exact physical structure and materials used to determine some type of result, which might be out of the scope for OptiSPICE. I would need to know a little more about what exactly you want to simulate to give you a straighter answer!