In order to eliminate the effect of amplitude modulation in the source with direct frequency modulation(DFM) on phase generated carrier(PGC) demodulation approach,a new PGC method was proposed based on differential-cross multiply(DCM) and double interferometric signals by a 3×2 directional coupler.Experimental results confirm that the new scheme has eliminated the effect of the companion amplitude modulation on demodulation very well.For a demodulation signal of 4 rad,the total signal-harmonic-r...