Hi,
OptiSystem is a physical layer simulation tool, you can investigate the performance of a system by measuring results such as BER. We do have examples of access networks and they can be seen at:
Whether you could simulate what you are interested depends on how high level it is. If you have a paper or outline of the type of simulations you want to run I could tell if it is possible. However, if you have access to Matlab you could definitely simulate an optical packet switching network. You could do all of the higher level simulation in Matlab and call OptiSystem from it to simulate the performance of your optical links.
Let me know if you have any questions!