Building on WDM, Dense Wavelength Division Multiplexing (DWDM) technology emerged in the early 1990s. The optical link between the terminals requires a data rate in the terabyte range which is typically realized by transmitting multiple wavelengths though one common channel. For. This study explores a hybrid communication link that combines fiber-to-the-x (FTTx) and free-space optical (FSO) technologies, utilizing ultra-dense wavelength-division multiple access (UD-WDMA) with a channel spacing of 0. 2 nm/25 GHz, under various weather conditions.