The Mass Rapid Transit (MRT) rail transportation system in Jakarta City requires fast and reliable connectivity, especially in the expansion coverage carried out in the MRT Phase 3 development project. One solution to providing reliable communication is the use of fiber optic networks. The speed and capacity of optical fiber have become the ideal parameters to support various communication applications. This paper proposed a design and analysis of an optical fiber network for the MRT Phase 3A, which covers the MRT development area starting limited in DKI Jakarta from Kalideres to Ujung Menteng with a track length of 31.7 km by considering SFP-1G-LX-SM transceiver and ITU-T G.654.B fiber optic cable. The parameters analyzed include the power-link budget and rise-time budget. The estimated received power based on the power-link budget ranges from -6.3025dBm in route 5 to -5.94dBm in route 21. These values are far from the receiver sensitivity of -20dBm due to the long distance between stations. The rise time budget analysis shows values ranging from 42.433 ps in route 21 to 42.484 ps in route 5, lower than the allowable rise time value. These results indicate the design is feasible to be considered in deployment.