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. 07, 1998
Filed:
Jul. 25, 1996
Brent E Little, Boston, MA (US);
Chi Wu, Nepean, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A polarization insensitive, multilayer planar reflection filter is provided having (I) strong sidelobe suppression, preferably with sidelobe suppression levels in the range of -30 dB to -50 dB, and (ii) minimum width of the filtered bandwidth for the specified sidelobe suppression level. The multilayer planar reflection filter is provided by a multilayer stack by specifying the manner in which the thickness of the individual dielectric layers are to be varied throughout the stack. The resulting universal design formula specifies these layer values for a stack with an arbitrary number of layers, dielectric constant, incident angle, and wavelength. In particular, the layer thickness values of the alternating layer d.sub.1 (j) in refractive index n.sub.0, and d.sub.2 (j) in refractive index n.sub.0 +.DELTA.n, vary with each period j and are determined to provide a specified central wavelength, sidelobe suppression and minimum filtered band width. The filter is polarization insensitive because the period required for maximum reflection at wavelength .lambda..sub.0 is the same for both TE and TM polarized light.