Method of making an article comprising an optical waveguide
AssigneeAT&T Bell Laboratories
InventorsRobert M. Atkins, Paul J. Lemaire, Victor Mizrahi, Kenneth L. Walker
Life of this patent
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Abstract
Unexpectedly large normalized refractive index changes (.DELTA.>10.sup.-5, but possibly even larger than 10.sup.-3) can be obtained in SiO.sub.2 -based optical waveguides (fiber or planar waveguides) by a treatment that comprises exposing at least a portion of the waveguide at a temperature of at most 250.degree. C. to H.sub.2 (partial pressure greater than 1 atmosphere), and irradiating at least a part of the exposed portion with actinic (typically UV) radiation.
Claims14
Method of making an article that comprises an optical waveguide, associated with the waveguide being a core, a cladding, a core refractive index and a cladding refractive index, the method comprising
- a) providing a waveguide that comprises high-silica glass,
- b) exposing at least a portion of the waveguide to H.sub.2 ;
- and
- c) irradiating at least a part of the exposed portion of the waveguide with actinic radiation such that the refractive index of the irradiated portion is changed;
- characterized in that
- d) step b) comprises exposing the waveguide at a temperature of at most 250.degree. C. to a H.sub.2 -containing atmosphere having a H.sub.2 partial pressure greater than 1 atmosphere, such that irradiation can result in a normalized index change (.DELTA.) of at least 10.sup.-5.
An article that comprises high-silica optical fiber having an axially uniform cross section, a core and a cladding surrounding the core, the core comprising less than 4.5 mole % GeO.sub.2, associated with the core and the cladding being a core refractive index and a cladding refractive index, respectively, wherein in a portion of the fiber the core refractive index varies periodically, with a repeat distance less than 100 .mu.m, with the normalized core index variation being at least 10.sup.-4, and with the cladding refractive index being substantially axially constant.
Dependencies are inferred from the claim text.