High-Index-Layer Coating on a Lensed Fiber Endface for Enhanced Focusing Power

Author

Shiraishi, Kazuo ; Kawasaki, Nobuyuki ; Yoda, Hidehiko ; Watanabe, Kenji ; Umetsu, Masato ; Hitomi, Tetsuya ; Muro, Koichi

Author_Institution

Grad. Sch. of Eng., Utsunomiya Univ., Utsunomiya

Volume

27

Issue

7

fYear

2009

fDate

4/1/2009 12:00:00 AM

Firstpage

864

Lastpage

870

Abstract

A new scheme for lensed fibers with a high focusing power is proposed. The new lensed fiber has a high-index layer coated (HILC) on a convex-shaped endface of a single-mode fiber (SMF). Numerical investigation shows that, by coating a 10-mum-thick film with refractive index of 3.7, the lensed fiber can contract the beam diameter of the propagating mode from 10.4 mum at the wavelength of 1.55 mum, to 1.2 mum. The enhanced focusing effect of the lensed fiber has been confirmed experimentally by coating an a-Si:H film on the lensed endface. The measured focused spot diameter was as small as 1.6 mum, much the same as the wavelength.

Keywords

coatings; elemental semiconductors; hydrogen; lenses; optical fibres; refractive index; semiconductor thin films; silicon; Si:H; enhanced focusing power; high-index-layer coating; lensed fiber endface; refractive index; single-mode fiber; size 10 mum; wavelength 1.55 mum to 1.2 mum; Coatings; Integrated optics; Optical fiber devices; Optical fibers; Optical films; Optical refraction; Optical variables control; Optical waveguides; Refractive index; Stimulated emission; Lenses; optical fiber connection; optical fiber devices; optical fibers; semiconductor lasers; spot size;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2008.927772

Filename

4814841