As one of the main detection schemes, phase generated carrier (PGC) technology has been implied in many fiber optic hydrophone array systems. The scheme requires a narrow bandwidth, tunable and low noise laser source. In practice, the relative intensity noise (RIN) of the laser has affected the system performance greatly. By analyzing the impact of RIN on fiber optic hydrophone’s PGC scheme theoretically, it has been found that if the RIN peak frequency can be controlled to odd multiple of one-half of PGC modulation frequency by changing the pump power, the impact of RIN on the system can be greatly reduced. Experiment results have proved that this scheme can lower the PGC noise from -86.7 dB to -106 dB. Furthermore, by using optical-electronic feedback, the RIN has been well suppressed and the relaxation oscillation peak is reduced about 25 dB. The laser noise has become -100 dB and the PGC output noise turned out to be -110 dB. This result has met the need of the fiber optic hydrophone systems.