Granted Patent
Utility
US 4,906,064 · App. 07/292,021
Switch for selectively switching optical wavelengths
Inventor:
Kwok Wai Cheung
Patented Case
View Patent ↗
Granted: Mar 6, 1990
Filed: Dec 30, 1988
Inventor
Kwok Wai Cheung
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.