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US 6,389,215 B1Granted
Low birefringent polyimides for optical waveguides statement regarding federally sponsored research or development
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsGeoffrey A. Lindsay, Andrew P. Chafin, Rena Yee, Peter Zarras
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Abstract
An optical waveguide subsystem, and process, having at least one cladding in contact with at least one core. The cladding has a refractive index less than the refractive index of the core. Either the cladding or core contains a crosslinked polyimide that is substantially meta-linked. The polyimide has an absolute birefringence of from about 0.01 to about zero.
Claims26
An optical waveguide subsystem comprising:
- at least one cladding in contact with at least one core, wherein the cladding has a refractive index less than the refractive index of the core;
- and,
- at least one of the cladding or the core comprises a crosslinked polyimide that is substantially meta-linked and has an absolute birefringence of from about 0.005 to about zero,
- wherein the polyimide comprises approximately 50 mole percent of at least one dianhydride residue and approximately 50 mole percent of a first diamine residue and at least an additional diamine residue, the first diamine residue formed from a diamine containing a crosslinkable reaction site.
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A process for fabricating an optical waveguide subsystem comprising the steps of:
- (a) forming a polyimide from about 2 mole percent to about 15 mole percent of a first diamine, wherein the first diamine possesses a crosslinkable site, from about 35 mole percent to about 48 mole percent of at least one additional diamine, wherein the combined first and additional diamines possess a substantial amount of meta-linking configuration and the combined mole percent of the first and additional diamines equals approximately 50 mole percent, and approximately 50 mole percent of a dianhydride;
- (b) forming-a solution of from about 20 weight percent to about 50 weight percent of the formed polyimide with from about 50 weight percent to about 80 weight percent of a solvent, and optionally from about 0.5 to about 10 weight percent of a crosslinking agent;
- (c) filtering the formed solution through a submicron filter;
- (d) spin-coating the filtered solution at from about 200 rpm to about 8000 rpm to form a film on a substrate;
- and,
- (e) baking the film at a final temperature which is the higher of from about 5° C. to about 30° C. above the glass transition temperature of the polyimide or approximately about 220° C. for a time period of from about 30 minutes to about 240 minutes.
3 more elements
Dependencies are inferred from the claim text.