Hello lukas,
I was just trying to run your system design. Although i couldn’t understand what exactly you are doing because of the complexity of your design but i guess it has got something to do with test set. I would like to suggest you to go through some of the examples in the optisystem samples regarding using the test set.
Also i tried to change your data rate which was in Mbps into Gbps. There is some logical error you are doing.
Regards