Granted Patent
Utility
US 4,919,504 · App. 07/353,407
Graded-index waveguides
Inventors:
Etienne G. Colas, Alfredo Yi-Yan
Patented Case
View Patent ↗
Granted: Apr 24, 1990
Filed: May 17, 1989
Inventors
Etienne G. Colas
Alfredo Yi-Yan
Assignee (at issue)
Bell Communications Research, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.