Single-lens equivalent systems for Grin lenses

In this paper, one simple single-lens optical systems equivalent to Grin lens of various lengths, which are immersed in either homogeneous or inhomogeneous medium, are proposed. Basing on this equivalent system, the imaging properties of Grin lens rod in paraxial approximation have been thoroughly studied. The proposed plain optical system will lead to a straightforward optical analysis of complex optoelectronics systems employing Grin lens rod.