A tapered graded-index lens: analysis of transmission properties and applications in fiber-optic communication systems

Author

Safaai-Jazi, Ahmad ; Suppanitchakij, Voravut

Author_Institution

Bradley Dept. of Electr. Eng., Virginia Polytech. Inst. & State Univ., Blacksburg, VA, USA

Volume

33

Issue

12

fYear

1997

fDate

12/1/1997 12:00:00 AM

Firstpage

2159

Lastpage

2166

Abstract

Propagation properties of a linearly tapered parabolic-index dielectric cylinder are studied using a ray-optics approach. Analytical solutions for trajectories of skew rays with arbitrary initial conditions are obtained for tapers with small slope and small index variations over transverse dimensions. Conditions for an arbitrary ray to remain bound to the core of the taper are derived. Applications of these tapered lenses for coupling of light sources to fibers, for beam expanding/refocusing in microoptics devices, and for splicing two fibers of different core sizes are addressed, Power coupling efficiency for illumination from both Lambertian and narrow-beam light sources are calculated. Improvement in coupling efficiency, when taper is are used to couple power from directed-beam sources to optical fibers, is demonstrated. Radiation losses when a taper is used as a transition element between two fibers of different core radii are evaluated. Plots of skew-ray paths, illustrating the gradual concentration of power as light travels toward the smaller end of the taper, are also presented

Keywords

gradient index optics; integrated optics; lenses; optical communication equipment; optical design techniques; optical fibre couplers; optical losses; optical waveguide theory; ray tracing; GRIN lens; Lambertian light sources; arbitrary initial conditions; arbitrary ray; beam expanding; beam refocusing; coupling efficiency; directed-beam sources; fiber-optic communication systems; linearly tapered parabolic-index dielectric cylinder; microoptics devices; narrow-beam light sources; power coupling efficiency; propagation properties; radiation losses; ray-optics approach; skew rays; skew-ray paths; small index variations; tapered graded-index lens; transmission properties; transverse dimensions; Dielectrics; Lenses; Light sources; Lighting; Microoptics; Optical coupling; Optical fiber devices; Optical fiber losses; Optical fibers; Splicing;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/3.644096

Filename

644096