Oh. It’s very simply in OptiSystem. In first, you can download any files here (https://optiwave.com/resources/downloads/optisystem-hot-topics/) and start simulation.
In second, you can make this scheme in new project. for example, open library, choose coherent transmitter, after that choose lenght fiber and coherent receive. In library you can find transmiiter for coherent QPSK, DP-QPSK, QAM16.