High speed data transmission was needed regarding technological improvements. DWDM and SDHs which are commonly used in optical systems provide high speed data transmission. On this work, working principles of DWDM and SDHs which are used in optical communication systems were investigated and also performance analyzes performed via OptiSystem 7.0 simulation program. In the analysis, an optical system which works with 193.1 THz frequency was modelled. Performances of the optical system's DWDM and SDHs were examined and compared on data transmission of communication systems.