Radio over fiber (RoF) technology has become the simplest pathway for distribution of the wireless signals in broadband wireless networks with the use of optical communication. It has gained popularity due to its advantage of providing high speed of data links with low cost. Third-order intermodulation distortion is the major parameter that significantly degrades the performance of RoF system. Therefore, in this paper a modified RoF system is proposed with Intensity-Modulation Direct Detection (IMDD) and Self-Interference Cancellation (SIC) to mitigate the effect of third-order intermodulation distortion. IMDD is considered as one of the simplest and widely used technique in order to reduce the nonlinearity in RoF system. The performance comparison in terms of third-order intermodulation distortion and third-order intercept point of IMDD based RoF system and the proposed system with IMDD and SIC has been investigated. An 18 dB reduction in third-order intermodulation distortion was observed in proposed system as compared to the IMDD based RoF system.