Research on the multi-longitudinal mode laser self-mixing static angle-measurement system using a right-angle prism

Abstract A static absolute angle measurement method using a right-angle prism as the angle-sensing device is developed for measuring the deflection angle by means of the multi-longitudinal mode laser self-mixing sensor. In the experiment, a laser diode operating at multiple excitation longitudinal modes is exploited as the optical source for deflection angle measurement. The measured self-mixing waveforms are in accordance with the simulated waveforms, of which demonstrate that the multi-longitudinal mode laser self-mixing sensor is available for measuring the deflection angle. Meanwhile, the angle-measurement range of the self-mixing sensing system is as many as ±6.00° corresponding to 0.20° angular resolution. Furthermore, both of the absolute angle measurement error and the linear correlation of the measured angle and the actual angle are further analyzed and investigated.