5G technology is increasingly present in various areas of application where it brings many opportunities that make everyday life easier. Therefore, it is constantly being worked on improving the performance of the 5G network, and thus the 5G RAN network that is an integral part of it. There are ways that are being explored to make this possible at an acceptable cost. One way is to apply optical communication systems. The topic of this work is the application of optical communication systems in the 5G RAN network which enables wireless connectivity to the users. The introductory part describes the concept of the 5G RAN network through its architecture and features. A RAN network based on C-RAN cloud computing is also described, which brings numerous advantages to the RAN network. The eCPRI protocol is analyzed in detail, as well as the ways in which optical communication systems are used for its implementation within the C-RAN network. The practical part elaborates the application of EPON and XG-PON technology in the C-RAN network. The queue delay for multiple cases is analyzed to show the features of these technologies which, in this paper, are selected as the representatives of optical communication systems in the C-RAN network. A comparison of GPON and XG-PON technology shows that XG-PON technology provides better system performance because it enables higher transfer rate for individual users and a higher ratio which means a larger number of users. Therefore, it is a much better solution to implement a 5G C-RAN network. A small cell has less variability and less latency when it comes to a specific limit for individual users. A small cell ensures better network bandwidth. The RRH unit provides less latency, but allows fewer users to be served.