DocumentCode :
1109554
Title :
Planar, buried, ion-exchanged glass waveguides: Diffusion characteristics
Author :
Ramaswamy, Ramu V. ; Najafi, S. Iraj
Author_Institution :
Department of Electrical Engineering, University of Florida, Gainesville, FL, USA
Volume :
22
Issue :
6
fYear :
1986
fDate :
6/1/1986 12:00:00 AM
Firstpage :
883
Lastpage :
891
Abstract :
A detailed theoretical and experimental study of Ag+-Na+ exchange in soda-lime silicate glasses in a molten bath containing a mixture of NaNO3 and Ag+ is presented. With no applied field, concentration profiles 
(and therefore, the index profiles for low concentrations) are given by complementary error function. The estimated value for the self-diffusion coefficient 
of Ag+ is 0.133 μm2/min for low concentrations and it monotonically increases with the surface concentration C0 until it saturates at about 0.3 μm2/min for 
MF. However, square root dependence of diffusion depth with time seems to be independent of the C0 . Presence of an external field 
causes the effective depth of diffusion to increase. In fact, for large fields, the profile can accurately be described by 
where 
where μ is the ionic mobility of Ag+in glass. We define a new diffusion depth 
as the distance from the surface to the 
concentration point, and for large fields, varies linearly with and 
. Experimental results yielded a value of 15.55 μm2/ 
min forμ. As before, square root dependence of with and the linear variation of versus C0 for 
MF, with saturating for 
MF, were observed in the case of field assisted diffusion. A two-step process, where a surface waveguide formed in the first step with either equal to zero or some finite value, is modified by performing a second diffusion in pure sodium nitrate to produce a buried, symmetrical fiber-like profile. This process is also studied in detail.
(and therefore, the index profiles for low concentrations) are given by complementary error function. The estimated value for the self-diffusion coefficient of Ag+ is 0.133 μm2/min for low concentrations and it monotonically increases with the surface concentration C MF. However, square root dependence of diffusion depth with time seems to be independent of the C causes the effective depth of diffusion to increase. In fact, for large fields, the profile can accurately be described by where where μ is the ionic mobility of Ag+in glass. We define a new diffusion depth as the distance from the surface to the concentration point, and for large fields, varies linearly with and . Experimental results yielded a value of 15.55 μm2/ min forμ. As before, square root dependence of with and the linear variation of versus C MF, with saturating for MF, were observed in the case of field assisted diffusion. A two-step process, where a surface waveguide formed in the first step with either equal to zero or some finite value, is modified by performing a second diffusion in pure sodium nitrate to produce a buried, symmetrical fiber-like profile. This process is also studied in detail.Keywords :
Optical planar waveguides; Planar optical waveguide; Glass; Integrated optics; Optical device fabrication; Optical fibers; Optical refraction; Optical surface waves; Optical variables control; Optical waveguides; Planar waveguides; Refractive index;
fLanguage :
English
Journal_Title :
Quantum Electronics, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9197
Type :
jour
DOI :
10.1109/JQE.1986.1073050
Filename :
1073050
Link To Document :
