Enhancement of heterodyne efficiency of heterodyne LADAR system with APD array detector based on array lighting

At the moment non-scanned imaging LADAR system whose advantage is rapidly imaging cannot work beyond a relatively short operating distance due to the restriction of laser power and attenuation of the signal. Therefore designing a new-type non-scanned heterodyne LADAR system with APD array detector is a imperative solution to this problem. The design of lighting systems is the concentration since different heterodyne efficiencies correspond to different optical systems and then decide the performance of the LADAR system directly. In this paper, it was discussed that the heterodyne efficiency of the system using a single expanded oscillator laser beam lighting system with a single collector lens stays only at 10-5 level which is far away from practical applications. Then, as a improvement design, array lighting theory was adopted with a micro lens array collector device played before the detector array, the maximum heterodyne efficiency of which reached 0.82 by calculation. The conclusion drawn in this paper proves the feasibility of array lighting heterodyne LADAR system theoretically and form the foundation for further research on heterodyne LADAR system with APD array detector.