The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 2001
Filed:
Aug. 20, 1999
Yihao Cheng, Kanata, CA;
JDS Fitel Inc., Nepean, CA;
Abstract
This invention relates to a method for filtering and to a variable slope optical filter for in-line use with an optical amplifier signal. The filter has a wavelength response that is substantially linear in slope within a band of operation wavelengths of the amplifier; the slope of the filter in an operating band of wavelengths is between zero and only one of a positive or negative number; furthermore the filter has an amplitude response that has an opposite and counter slope as a function of wavelength to that of a gain tilt of the amplifier within the operation band of wavelengths. The filter having means of operating on polarized light such that different wavelengths within a band of wavelengths within the operation band are subject to different levels of attenuation according to their polarization state. A wave plate having a predetermined thickness provides a relative polarization difference between two wavelengths of an incoming beam in a controlled manner. A polarizer receives light from the wave plate and only allows a predetermined polarization of light to pass therethrough unattenuated and variably attenuates or substantially prevents and/or attenuates other predetermined polarizations of light to pass therethrough.