一种消除伴生调幅的光源调频型相位生成载波解调方法

Frequency-modulated phase generated carrier demodulation for eliminating companion amplitude modulation

为了克服伴生调幅对光源调频型相位生成载波(PGC)解调方法的影响,提出一种基于双路干涉信号和微分-交叉相乘(DCM,differential-cross multiply)的PGC解调方法。通过3×2耦合器引入双路干涉信号,直接调制光源频率获得相位载波。实验结果表明,新方法较好地消除了光源伴生调幅的影响。对于4 rad的解调信号,总谐波比提高20 dB以上,幅值偏差为0.08 rad,而单路干涉信号的DCM-PGC方法的偏差达0.33 rad。并且,新方法的信噪比和信纳比均有显著的改善。

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-ratio（SHR） increases by more than 20 dB,and the amplitude deviation of this new method is 0.08 rad,while it is up to 0.33 rad by the DCM-PGC approach for a single interferometric signal.Besides,the signal-tonoise ratio（SNR） and signal-to-noise-and-distortion（SINAD） are also improved significantly.