Granted Patent
Utility
US 4,979,790 · App. 07/426,870
Guided-wave optical wavelength duplexer
Inventor:
Robert G. Walker
Patented Case
View Patent ↗
Granted: Dec 25, 1990
Filed: Oct 26, 1989
Inventor
Robert G. Walker
Assignee (at issue)
Plessey Overseas Limited
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.