This paper presents the characteristics of phase ripple which can impact on the performance of wave division multiplexing passive optical network (WPON) dealing with 30 MHz of transmission bandwidth. The relationship between performance and phase-ripple was obtained through theoretical analysis. Also, phase-ripple parameters of surface acoustic wave (SAW) filter in RF transceiver, the group delay variation and the slope of group delay, were taken into consideration for performance evaluation of WPON. In order to meet 30 dB of system performance requirement, 40 ns below of group delay variation and 2 ns below of group delay slope are required through simulation and test results.