In this paper, the particle swarm optimization (PSO) algorithm is used to optimize the performance of a radio over fiber system against cross-phase modulation (XPM) crosstalk by finding the optimum value of crosstalk by independently considering the range of various fiber parameters in the V band (40 to 75 GHz) and W band (75 to 110 GHz). Results show that, without using any optimization technique, the crosstalk is found to be minimum at the small frequency in both frequency bands. Without optimization, XPM crosstalk is found to be −62.2, −56.2, and −52.7 dB at 40 GH, 75 and 110 GHz, respectively, at the fiber length of 20 km, whereas after PSO, XPM crosstalk is −65.4 and −71.9 dB at 75 and 110 GHz, respectively, at the high fiber length of 50 km. After applying the PSO optimization technique, XPM crosstalk is optimized with the minimum at high frequencies in both frequency bands at large fiber lengths. It is found that XPM is optimized at different values of the dispersion parameter without the use of a dispersion-shifted fiber. Joint optimization is also done for the complete range of frequencies from 40 to 110 GHz, and optimized crosstalk is obtained independently at high frequencies and large fiber lengths in both frequency bands. From the results, it can be seen that a radio-over-fiber system can be designed by choosing a single-mode fiber with the optimized parameter value. The XPM crosstalk keeps increasing with the increase in the length of the fiber and frequency, and PSO was used to counter the crosstalk by optimizing the various fiber parameter values.