Title :
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
fDate :
8/1/1990 12:00:00 AM
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;
Journal_Title :
Lightwave Technology, Journal of
