Beam expanding fiber using thermal diffusion of the dopant

Author

Shiraishi, Kazuo ; Aizawa, Yoshizo ; Kawakami, Shojiro

Author_Institution

Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan

Volume

8

Issue

8

fYear

1990

fDate

8/1/1990 12:00:00 AM

Firstpage

1151

Lastpage

1161

Abstract

A beam-expanding fiber (BEF) for embedding optical devices has been fabricated by utilizing thermally induced Ge diffusion in silica single-mode fibers (SMFs). The preparation of fiber samples and their heat treatment is described, and the effect of heat on Ge dopant distribution and diffusion is discussed. Modal-intensity distributions were studied and found to confirm the broadening of the modal field distribution after heat treatment of the fiber. Localized heat treatment to obtain BEFs is considered, and device characteristics are discussed. The BEF can arbitrarily change the spot size of a propagating mode without changing the normalized frequency

Keywords

elemental semiconductors; fibre optics; germanium; heat treatment; thermal diffusion; Ge dopant distribution; beam-expanding fiber; dopant; heat treatment; modal field distribution; modal intensity distribution broadening; model-intensity distributions; normalized frequency; optical device embedding; optical fibre fabrication; propagating mode; silica single-mode fibers; spot size; thermal diffusion; thermally induced Ge diffusion; Frequency; Lenses; Optical devices; Optical fiber devices; Optical fiber polarization; Optical propagation; Optical refraction; Optical variables control; Silicon compounds; Thermal expansion;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/50.57835

Filename

57835