Optical Design software provides an optical designer with a set of tools to evaluate and test the performance of an optical system or apparatus. It is commonly done with a set of visualization tools and a list of activities for the creation of an optical system.
What is optical simulation?
Simulations support the development of optical systems When developing optical systems and components like this multi-reflection cell, simulations help to evaluate the influence of different variables on the optical properties of a component.
Is there any free open source software for optical component design?
You may try OptiWave FDTD if it is suitable. It is free.