Long Range Raman-Amplified Distributed Acoustic Sensor Based on Spontaneous Brillouin Scattering for Large Strain Sensing.

A Brillouin distributed acoustic sensor (DAS) based on optical time-domain refractometry exhibiting a maximum detectible strain of 8.7 m and a low signal fading is developed. Strain waves with frequencies of up to 120 Hz are measured with an accuracy of 12 at a sampling rate of 1.2 kHz and a spatial resolution of 4 m over a sensing range of 8.5 km. The sensing range is further extended by using a modified inline Raman amplifier configuration. Using 80 ns Raman pump pulses, the signal-to-noise ratio is improved by 3.5 dB, while the accuracy of the measurement is enhanced by a factor of 2.5 to 62 at the far-end of a 20 km fiber.

研制出一种基于光时域折射测量法的布里渊分布式声学传感器（DAS），其最大可检测应变为8.7米，信号衰落低。在8.5千米的传感范围内，以1.2千赫兹的采样率和4米的空间分辨率，对应变波频率高达120赫兹的测量精度为12微应变。通过采用改进的在线拉曼放大器配置进一步扩展了传感范围。使用80纳秒的拉曼泵浦脉冲，在20千米光纤的远端，信噪比提高了3.5分贝，同时测量精度提高了2.5倍，达到62微应变。