High-Sensitive Fiber Optical Accelerometer With Pulse Modulation of Optical Flow Intensity

Abstract

This research addresses to the design and development of a precision fiber optical sensor of acceleration using pulse modulation of optical flow intensity. The accelerometer proposed in this article can theoretically reach a threshold sensitivity better than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> g (~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) for acceleration near g and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-13</sup> g (~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) for ultralow acceleration. In addition to the high resolution, it is possible to adjust the frequency of acceleration measurement by changing the parameters of the sensor, which allows the device to be applied to specific tasks. In our experiment, we assessed the changes in acceleration constrained by seismic noise. As a result, the noise levels were measured on the order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> g for the vertical component and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> g for the lateral components. Furthermore, the minimum detectable acceleration changes were observed at levels of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> g for the vertical component and 5×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> g for the lateral components. The proposed acceleration sensor has several advantages compared to current developments, such as immunity to external electromagnetic fields and measurement of time instead of measuring optical force to determine acceleration. Moreover, theoretically, the relative error level is comparable to the advanced developments in the field of acceleration measurement, while the mass and size characteristics of the proposed sensor are superior to conventional measuring instruments.