Method for measuring acceleration by the spectrum of self-mixing signal of semiconductor laser

Background and Objectives: Traditional methods for measuring the acceleration by changing the position of extremums on the time axis, as well as methods based on the use of least squares and wavelet analysis, require significant signal processing efforts: filtering and allocating extremums or significant time for processing an autodyne signal. The proposed method for measuring the acceleration of the spectrum of the self-mixing signal uses a well-established machine method of Fourier analysis, which is widely used for processing complex waveforms. Materials and Methods: The self-mixing signal spectrum has been simulated at the uniformly accelerated movement of the reflector. The interconnections of the low-frequency and high-frequency components of the self-mixing signal spectrum have been shown. The cases of measuring the uniformly accelerated object motion along the spectrum of a self-mixing signal have been experimentally implemented. Accelerated movement of the reflector was carried out using signal generators embed into the laboratory station of virtual instruments NI ELVIS. The results of measuring the motion of piezoceramics with acceleration are given, which are specified by the quadratic law of the change in voltage. Results: For the most common case of moving an object at zero initial velocity, a linear dependence of the high-frequency spectral component at the end of the observation interval on the acceleration has been observed. The proposed method, when used as a laser radiation source with a wavelength of 650 nm, allows to determine accelerations exceeding $1 \mu m/s^2$. The results of calculating the acceleration from the self-mixing signal spectrum for the case of $a = 26 \mu m/s^2$ have been shown. Conclusion: The method of acceleration measurement based on Fourier analysis of laser autodyne interference signal has been proposed. The resolution of the proposed method has been evaluated by changing the frequency of the spectral component per unit and amounted to $500 nm/s^2.$