High-speed data transmission over long distances is a big challenge in the telecommunications world. Therefore, a reliable communication network is needed to provide this service to subscribers. Fiber optics is based on Fiber to the Home (FTTH / GPON) network, which is a fiber optic architecture that uses fibers as transmission channels to customers' homes or offices. In this proposed paper, the optical fiber analysis to the houses at different lengths (5-35km) presented and discussed. The transmission power was set to 5 dBm, from the results of the design optisystem tools, when the optical fiber length was 5km length the minimum bit error rate BER obtained = 0, where the length has been changed to 35km, the BER increased and the quality factor decreases gradually as the fiber length increases to reach the lowest value Q= 6.573 and BER=2.4589×10-1. FTTH / GPON technology can be applied for specific distances in cities where cost is reduced and data transmission rates are increased.................... Keywords........... FTTH; Optical Fiber; minimum bit error rate; GPON networks.