High-Measurement-Range Optical Accelerometer: A Movable Micromirror Method

Compared to traditional accelerometers, optical accelerometers exhibit remarkable performance in terms of electromagnetic interference resistance, sensitivity, temperature stability, and environmental adaptability. However, the current measurement range of the optical accelerometer is limited, which restricts the application in demanding scenarios, e.g., aerospace equipment and explosion fields, where accelerations can easily exceed that bound. To tackle this, this article proposes an optical accelerometer based on a movable micromirror affiliated with a spring-mass structure. The displacement of the micromirror controls the optical transmission from the input to the output fiber. Specifically, the spring-mass structure detects the external acceleration and converts it into displacement, which subsequently modulates the luminous flux from the output fiber that can be read out as an optical voltage using a photodiode. In this scheme, the micromirror’s measurable displacement and stiffness-to-mass ratio have both reached large scales, i.e., 55– 90 µm and 7.7 × 10⁸ N/(m · kg ), respectively. This leads to a high acceleration measurement range of 3500–5500 g, significantly surpassing the existing limits. Moreover, the sensitivity is 0.092 mV/g, which is sufficient for such a wide measurement range. It changes by only 2.17% under a 4000-g impact, indicating excellent stability and repeatability of performance. This work is expected to significantly enhance the application of optical accelerometers in high-gravity impact environments.