根据光外差检测原理，分析得到干涉测量适用于信号光强小于参考光强的探测，直接测量适用于信号光强大于参考光强的探测的结论。利用自制的全光纤马赫－曾德尔干涉仪系统，对位移信号进行了测量。实验结果表明：当位移信号较小时，干涉测量的灵敏度分别为62．068μW／mm和9．90mV／mm，而非干涉测量的灵敏度分别为4．30μW／mm和0．35mV／mm；当位移信号较大时，干涉测量的灵敏度分别为2．643mV／mm和0．055mV／mm，非干涉测量的灵敏度分别为12．326mV／mm和4．194mV／mm，测量结果与分析得到的结论一致。对于光纤干涉仪强度调制检测的应用具有参考价值。

According to the principle of optical heterodyne measurement, the interferometry is suitable for the signal whose intensity is weaker than reference signal, while the non-interference survey (direct measurement) is suitable for the signal whose intensity is stronger than reference signal. By using our self-made all optical fiber Mach-Zehnder interferometer, the displacement signal is measured. The experiment results show that the sensitivity of interference measurement is respectively 62.068 μW/mm and 9.90 mV/mm, and the sensitivity of non-interference measurement is 4.30 μW/mm and 0.35 mV/mm when the amount of displacement is lower. When the displacement is larger, the sensitivity of interference measurement is respectively 2.643 mV/mm and 0.055 mV/mm and the sensitivity of non-interference measurement is 12.326 mV/mm and 4.194 mV/mm. The experiment results are in keeping with the conclusion of our analysis. This work makes reference for the application of the intensity modulation measurement of all optical fiber interferometer.