DUNE will be an underground neutrino oscillation experiment that will perform precision measurements of the PMNS mixing parameters, determine unambiguously the mass ordering and discover leptonic CP violation. It also comprises a rich non-accelerator physics program as the detection of supernova neutrinos, nucleon decay and BSM physics. One of the modules of the DUNE is proposed to be Dual-Phase LArTPC. Inside this module, a light detection system (LDS) is being designed, consisting on an array of photomultiplier tubes and a calibration system based on optical fibers. To fulfil the physics program, the LDS is aimed to comply with certain physics requirements. Those are to provide a detection efficiency of more than 90% for a Supernova Burst within the Milky Way and an event time reconstruction efficiency of more than 90% with a signal purity of more than 90% across the active volume for proton decay event candidates. The present document summarizes the status of the simulation studies of the light detection in DUNE Dual-Phase, and the expected performance of the LDS, that will be part of the forthcoming Technical Design Report of DUNE.