Design of fused optical fiber bundle for ground based lidar receiver to profile the lower atmosphere

Abstract

In this paper, we propose an optical fiber design for a wide field of view (WFOV) lidar receiver. The proposed system intends to collect aerosol backscatter and aims to profile the lower atmosphere from 8m onwards. We determined overlap function of lidar for various aperture stop diameters. As per our analysis, a fiber diameter of 21mm is required at the focus point of telescope to obtain the full overlap at 8m altitude. Since, it is impractical to realize such a large core diameter fiber of 21mm, we propose a field lens to converge the blur disk to 3mm spot size. To collect the focused beam, we propose to use a fused fiber bundle of 3.5mm diameter. The fused fiber offers extraordinary capturing efficiency and projects an effective mode capturing area of 5×10−8mm2. We present the fused fiber design details and compare its performance with hexagonal array fiber bundle.