论文部分内容阅读
针对光纤干涉仪存在的相位衰落问题,讨论了基于正弦波形的频率调制连续波(FMCW)和锯齿波FMCW两种干涉型光纤声传感器的信号检测原理,并给出了数字化信号解调方案。采用7.5 m臂差的光纤声传感器和具备调频功能的半导体激光器,对10 kHz正弦波FMCW和锯齿波FMCW两种调频方式进行了信号解调实验对比。解调结果表明,两种调制解调方案均能稳定检测出加在声传感器上的模拟声信号,消除了光纤干涉仪的相位衰落。但在实际工程应用中,与正弦波FMCW检测方案相比,锯齿波FMCW方案无需检测混频信号的初始相位,检测灵敏度高且稳定,算法实现更为简单,而且使用不同臂差的光纤传感器可实现传感器的频分复用。
Aiming at the problem of phase fading in optical fiber interferometer, the principle of signal detection based on sinusoidal waveforms of FMCW and sawtooth wave FMCW is discussed, and the digital signal demodulation scheme is given. An optical fiber acoustic sensor with 7.5 m arm difference and a semiconductor laser with frequency modulation function were used to demodulate the two frequency modulation modes of 10 kHz sine wave FMCW and sawtooth wave FMCW. Demodulation results show that both modulation and demodulation schemes can stably detect the analog sound signal applied to the acoustic sensor and eliminate the phase fading of the optical fiber interferometer. However, compared with the sine wave FMCW detection scheme, the saw-tooth FMCW scheme does not need to detect the initial phase of the mixed signal in practical engineering applications. The detection sensitivity is high and stable. The algorithm is simpler and the fiber sensor with different arm tolerance can be used Achieve the sensor’s frequency division multiplexing.