High-bandwidth and high-thermal-stability graded-index polymer optical fiber

Abstract

ABSTRACT Recent progress of the graded-index polymer optical fiber (GI POF) is reviewed. Because the low attenuation of lighttransmission in the perfluorinated (PF) polymer base GI POF enables 500 to I 00 0 m transmission, more accurate analysis isrequired in the refractive index profile to realize the order of giga bit transmission. The analytical procedure of thebandwidth characteristics of the GI POF is described in this paper. Furthermore, recent improvement of the thermalstability of the GI POF is introduced. We clarified that the stability of the refractive index profile and the attenuationunder high temperature and high humidity atmosphere can be improved by selecting the suitable dopant material.Keywords: graded-index polymer optical fiber (GI POF), perfluorinated (PF) polymer, scattering loss, absorption loss,refractive index profile, modal dispersion, material dispersion, thermal stability, glass transition temperature (Tg) 1 INTRODUCTION Considerable research activity lately has been focused on the development of the optical component and devices that havethe capability to support the high-speed multimedia network. Silica base single mode optical fiber is widely utilized in thelong distance trunk area for the order of giga bit per second transmission because of its high bandwidth and transparency.On the other hand, the conventional metallic cables in the access area network significantly limit the transmission rate to theorder of kilo bit per second. However, introduction of the single mode fiber in such short-range network requires manybreakthroughs in the total system cost. Because of the small core size such as 5 to 1 0 rim, accurate alignment is necessaryin the light coupling to the fiber and the connection ofthe fiber, which increases the cost ofthe optical devices such as fiberconnectors for the single mode fiber systems.We have proposed a large-core, high-bandwidth, and low-loss GI POF2. Large core such as 300 —100 0 tm ofthe GI POF enables the use of inexpensive polymer connectors, which is prepared by the injection molding. Since the poly(methyl methacrylate) (PMMA) has been generally used as the core material of step-index type POF commercially available,its attenuation limit is approximately 100 dB/km at the visible region3'4. Therefore, the high attenuation of POF compared