Analyses on propagation and imaging properties of GRIN lenses

摘要

GRIN lenses, graded-index lenses, are widely used to construct micro-optic devices such as optical coupler, connector, beam splitters, optical attenuator, beam expanders, optical fiber switch and WDM, etc. Grin lens should be designed according to different uses to meet some special requirements. It is essential to realize the properties of propagation and imaging. Propagation properties and image properties of two kinds of Grin lens, respectively parabolic-index dielectric cylinder GRIN lens and tapered cylinder GRIN lens, are described in this paper. The propagation properties are studied using a ray-optics approach. We denote the passage of a ray through these GRIN lens can be described by simple 2X2 matrices. The parameters of this two kind GRIN lenses, such as focal length and magnifying power are given in this paper meanwhile. Comparison between cylinder GRIN lenses and tapered cylinder GRIN lenses is done in applications for coupling of light sources to fibers, beam expanding/refocusing in micro-optics devices, and splicing two fibers of different core sizes.