A four-element photomixer receiver has been tested in a 10-μm heterodyne Doppler lidar. It addresses a reduction of the variance of the power scattered off distributed aerosols targets at ranges as long as 8 km. An improvement in performance is expected when the four independent signals recorded on every single shot are combined. Two summation techniques of the four signals have been implemented: a coherent summation of signal amplitude and an incoherent summation of intensities. A phasing technique for the four signals is proposed. It is based on a more suitable correlation time with discernible self-consistent packets (SCP’s). The SCP technique has been successfully tested, and the results obtained with a coherent summation of the four signals, i.e., variance reduction, carrier-to-noise ratio improvement, and velocity accuracy improvement, are in agreement with theory.
© 2000 Optical Society of America
(030.1670) Coherence and statistical optics : Coherent optical effects
(030.6140) Coherence and statistical optics : Speckle
(040.2840) Detectors : Heterodyne
(280.3640) Remote sensing and sensors : Lidar
Xavier Favreau, Arnaud Delaval, Pierre H. Flamant, Alain Dabas, and Patricia Delville, "Four-Element Receiver for Pulsed 10-μm Heterodyne Doppler Lidar," Appl. Opt. 39, 2441-2448 (2000)