The topic of the final paper is passive optical networks with wavelength division multiplexing. The WDM multiplexing technique multiplies the capacity of optical fibers, as there is no interference between individual light wavelengths. Each wavelength can emit one stream of data. The basic subtypes of WDM are CWDM and DWDM. A passive optical network has no active components between the central office and the user. The network transmission path uses exclusively passive optical components to transmit light signals at precisely defined wavelengths. The optical line terminal is located at the central office, while the optical network unit is on the user's side and they represent active parts of the equipment. The optical distribution network constitutes their link, representing all passive components of the network. Several different types of architectures for practical implementation of the WDM-PON network will be defined based on the requirements and needs of subscribers, with cost being a decisive factor among others. As a potential solution for future user needs, the WDM-PON network offers the following advantages: high transmission speeds, one fiber serves a large number of users, and service transparency.