title: Research on heterodyne detection of a mode-locked pulse laser based on an acousto-optic frequency shift.
abstract: Heterodyne detection research is carried out on a mode-locked pulse laser using an acousto-optic frequency shifter (AOFS). Theoretical calculation and numerical simulation of the beat frequency of the mode-locked pulse were carried out, and the results show that the frequency offset can be calculated according to the beat period of the pulse waveform, and the offset is the frequency difference between the two adjacent longitudinal modes. Experiments were implemented with a self-built mode-locked laser using an AOFS to simulate the frequency shift of the detection laser induced by the object, the coherent beat frequency of the signal light and local oscillation light that were observed on the surface of the detector. The beat frequency wave was processed by filtering to obtain the frequency shift of the signal light. The experimental results are in good agreement with the numerical simulation.
authors.affiliation: National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001, China. xiaobai0453@163.com
authors.forename: Yan
authors.initials: Y
authors.lastname: Bai
authors.forename: Deming
authors.initials: D
authors.lastname: Ren
authors.forename: Weijiang
authors.initials: W
authors.lastname: Zhao
authors.forename: Liming
authors.initials: L
authors.lastname: Qian
authors.forename: Zhenlei
authors.initials: Z
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu