The pilot-assisted peak-to-average power ratio (PAPR) reduction technique proposed for optical orthogonal frequency division multiplexing (OFDM) communication systems is evaluated empirically and theoretically in this letter. The PAPR reduction is achieved by rotating the phase of data symbols with $P$ iterations of randomly generated pilot symbol sequence. The results of our hardware implementation and analysis show a close agreement to that of computer simulations. In comparison with basic OFDM, where no PAPR reduction technique is implemented, experimental PAPR reduction gain of pilot-assisted OFDM at a complementary cumulative distribution function of $10^{-3}$ with $P=5$ is $\sim 2$ dB. This gain is $\sim 0.2$ dB less than that of analytical results. The experimental results also show that the pilot-assisted technique does not cause any significant deterioration of the bit error performance.