Abstract

A 1.55 micron Coherent Doppler laboratory Lidar system has been developed to study the enhancement in the measured lidar SNR through the use of a dual aperture balanced heterodyne array using incoherent and coherent summation of the detected array signals. Figure 1 shows a schematic of the Doppler lidar (laboratory) system. A 30 mW, 1.55 micron, single frequency diode laser is used as the main excitation source. The beam is split into a LO channel and a main projected beam followed by a 27 MHz AcoustoOptic shifter. The main portion is sent to a rotating target and the reflected backscatter is col-lected by two spatially separated single mode, polarization preserving fibers. The two collected signals are branched into inphase and quadrature signals for balanced heterodyne detection. The four channels are detected and the electrical signals are analyzed using spectrum analyzers, 4 channel oscilloscopes, and computer interfaced.

© 2002 Optical Society of America