Granted Patent
Utility
US 6,174,648 · App. 09/109,904
Optical filter fabrication method using fiber holder with spiral groove and phase mask with spiral diffraction grating
Inventors:
Yoshitaka Terao, Tsutomu Nomoto, Akihiko Nishiki
Patented Case
View Patent ↗
Granted: Jan 16, 2001
Filed: Jul 2, 1998
Inventors
Yoshitaka Terao
Tsutomu Nomoto
Akihiko Nishiki
Assignee (at issue)
OKI ELECTRIC INDUSTRY CO., LTD.
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.