抗温度干扰光纤声传感器

In this paper, a temperature insensitive fiber acoustic sensor with a π/2 quadrature phase plate is proposed. A wavefront phase plate with π/2 quadrature phase is fabricated by micromachining technology. Beam collimation through a self-focusing fiber can create wave interference through the π/2 quadrature phase plate, thus forming a miniature quadrature interference acoustic sensor. The experimental results show that when an acoustic frequency of 0.1-10 kHz for the proposed sensor, the acoustic response sensitivity reaches 168 mV•Pa^-1 and the minimum detectable acoustic pressure can be 68 μPa•Hz^-1/2 at a frequency of 5 kHz. Notably, the proposed sensor is almost insensitive to temperature fluctuation because of the fixed quadrature phase of the π/2 quadrature phase plate. The voltage standard variation of the proposed sensor is only 2.4% in a wide range from 20℃ to 140℃. The proposed sensor is very promising in several applications in remote gas leak exploration, photoacoustic spectroscopy detection, and sound location.