The principle of measuring instantaneous frequent and dynamic linewidth of frequency swept lightwaves

Much effort has been focused on the development of frequency modulation continuous waves (FMCW) light sources which are used in Light Detection And Ranging (LiDAR) systems. However there has not appeared a method or instrument which can measure the instantaneous frequency and dynamic linewidth of the FMCW light source over the whole frequency sweep range of about several hundreds of GHz with an accuracy down to kHz. In this paper a new method is proposed for measuring the dynamic frequency properties of FMCW light sources in real-time and several experimental setups are built for the feasibility study.