Novel method of generation of linear frequency modulation optical waveforms with swept range of over 200 GHz for lidar systems

Abstract

Light detection and ranging (lidar) is used for various applications such as remote sensing, altimetry and imaging. Continuous wave frequency modulated (CWFM) lidars rely on linearly ramping the optical frequency of a laser and interfering the delayed echo signal with a reference signal to produce a beat frequency. The range resolution of lidar is determined by the swept frequency range of the linearly chirped continuous light waves in a frequency modulation system. For example, for 1mm range resolution, it needs the frequency sweep range of more than 150 GHz. In this paper a system which can generate a linearly chirped optical waveform within a super broad-wide band of 200 GHz, using cascaded phase modulators (PM) and single side band (SSB) modulator, is designed as a light source in a high resolution lidar system.