Moving from lower RF range to high frequency range is highly required technology because of the massive rise in required non-wired transmission subscribers and high data rate required per customer. By providing capacity, simple design and low cost, RoF system has been acknowledged as the foundational technology for 6G networks. This paper presents variation in optical RF power and RF power-to-noise power ratio (SNR) by varying the optical amplifier gain from 20 to 40 dB and fiber distance from 5 to 25 km. The result shows that optical RF signal power decreases with the decrement in the optical amplifier gain and increment in the optical fiber length. Similarly, RF signal power-to-noise power ratio gradually increases with increment in optical amplifier gain and decrement in fiber length.