Design Optimization for High Manufacturability of Optical Fiber Endcap for Range Detection LADAR

Abstract

High power fiber laser module of the transmitting channel for the designed LADAR (LAser raDAR) system has an angled endcap to avoid the direct reflection fed back to the source laser unit. However, the reference endcap design shows low manufacturability caused by the technical challenge in splicing and fabrication. We explored four alternative design solutions exhibiting similar performances. The end cap design compatibility was achieved with the transmittance and beam shape analysis using a non-sequential ray tracing program, ASAP. Specially, the analysis was focused at the zoom lens position and the endcap position. Among the four designs, the best solution shows the transmittance of about 89% of the Reference Design with 0.14° LOS (Line of Sight) shift. We believe that 11% in absorption by the mechanical components and can be further improved with the minor mechanical change and that the LOS shift is within the accommodation range of the wedge compensators in the transmitting channel.