Abstract: Single-mode VCSEL (vertical cavity surface emitting laser) laser self-mixing LDV (laser Doppler velocimeter) system is superior to multimode laser LDV system in temperature characteristics and the range of external cavity length L_(ext). Using the signal processing technology of differential frequency analog phase-locked loop, the speed measurement accuracy and dynamic range of single-mode VCSEL self-mixing LDV are obviously improved. The frequency division tracking triangular wave current modulation technology with Doppler frequency shift f_d is adopted to improve the accuracy and dynamic range of motion direction discrimination. The experimental results show that the resolution is better than the traditional method when the external cavity length is 30 mm 3 mm, the temperature is 0℃ ~ 55℃, the sampling time is 0. 1s and the laser does not control the temperature. In the range of 30 ~ 480 mm/s, the speed measurement accuracy is better than 65438 0%. When the speed range is 5 ~ 480 mm/s, the speed measurement accuracy is better than 2%. When the power supply voltage is 5V, the indication level of the forward movement direction is greater than 4.9V, and the indication level of the reverse movement direction is less than 0.1v. 。

Authors: Physics Department of China University of Science and Technology, Physics Department of China University of Science and Technology, Physics Department of China University of Science and Technology, Physics Department of China University of Science and Technology, Physics Department of China University of Science and Technology, Physics Department of China University of Science and Technology.

Keywords: laser technology Single-mode VCSEL self-mixing LDV analog differential frequency phase-locked loop Direction finding and speed measuring accuracy Multi-mode laser dynamic range temperature characteristics analog phase-locked loop

Classification number: TN248

Text snapshot:

1 Introduction As a non-contact velocity measurement technology, self-mixing LDv of semiconductor laser has a good application prospect. Usually, the accuracy of speed measurement, direction discrimination, dynamic range, variable range of external cavity length and temperature characteristics are the main parameters closely related to the application. The temperature characteristics of self-mixing LDV of multimode laser are poor, and the variable range of external cavity length is small, so it is generally necessary to control the laser at a constant temperature. VCSEL has