Simultaneous distance and vibration mapping of FMCW-LiDAR with akinetic external cavity diode laser
Hansol Jang, Jeong Won Kim, Gyeong Hun Kim, Chang Hyun Park, Seung Won Jun, Minsik Jo, Hwidon Lee, Chang‐Seok Kim
Abstract
In this study, the simultaneous distance and vibration mapping of frequency-modulated continuous-wave light detection and ranging (FMCW-LiDAR) is performed using an electro-optical external cavity diode laser (ECDL). Owing to the akinetic operation regime of the ECDL, a uniform (R2 = 1.0000) interference signal can be generated over a bandwidth of 1 GHz at an optical frequency sweep rate of 10 kHz without any postprocessing or system for linearization. Furthermore, the proposed ECDL exhibits a high optical frequency sweep rate of 200 kHz with a considerable linearity of R2 = 0.99975. Based on a point sensing experiment using the FMCW-LiDAR system, three measurands, namely, distance, vibration frequency, and vibration velocity change, are demonstrated with a highly linear relationship between the beat frequency and amplitude of each individual parameter. Furthermore, temporal variations in multiple targets with rapidly frequency-varying vibrations, such as those occurring in music or voice sounds, can be successfully acquired by tracking the temporal change in the beat frequency of each target. Moreover, three-dimensional (3D) mapping of distance, vibration frequency, and vibration velocity change is simultaneously implemented in the same 3D space. The results show that the proposed FMCW-LiDAR system can be used for the 3D visualized display of various measurands within the same space frame.