Polarization nonreciprocal phase error is one of major errors in fiber optic gyroscope (FOG). In dual polarization FOG, the polarization nonreciprocal phase error in two orthogonal polarization modes possesses opposite signs, which can be compensated optically. The influences of light source on performance of dual polarization FOG are discussed based on the dual polarization FOG theory and model, which shows that the bias stability of dual polarization FOG is improved by short coherence length and low degree of polarization (DOP). Experiment results show that super luminescent diode (SLD) or super-fluorescent sources (SFS) can be adopted to compensate polarization nonreciprocal error effectively under conditions of short coherence length and low DOP in dual polarization FOG.