Vol. 18, issue 10, article # 13

Abstract:

The lidar equation for cw lidars with linear frequency modulation (LFM) of the sensing beam intensity is under analysis. Photo-resistor operation under radio-heterodyning regime (RHR) is analyzed. It is shown that RHR provides for multiple reduction of the received signal threshold power and correspondingly increase energy characteristics of infrared cw LFM lidars. Principles of operation of the coherent LFM lidar with reference beam phase conservation are considered. It is shown that the artificial phase conservation (with the help of optical fibers) provides for multiple lengthening (by about 10⁵ times) of the sensed path at conservation of mutual coherence of the reference and received beams. This allows application of laser diodes in the systems with the operation range up to 10 km.