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:
Apr. 13, 2004
Filed:
Jul. 19, 2002
Markus Tilsch, Santa Rosa, CA (US);
JDS Uniphase Corporation, San Jose, CA (US);
Abstract
Thin film filters have been a basic building block of many wavelength division multiplexed (WDM) systems providing the means by which a signal, defined by a center wavelength, can be separated from a group of WDM signals. In an effort to maintain the same performance over a range of operating temperatures, thin film filters have been coated onto specially designed substrates, which expand and contract with the change in temperature to counteract the effects that the temperature change has on the thin film filters. Unfortunately, only very few materials provide the necessary thermal expansion characteristics to counteract the shift in center wavelength. Moreover, the application of a force onto only one side of the filter causes the thin film filter to bend or curve. Accordingly, the present invention solves the aforementioned problems by providing a thin film filter sandwiched between a substrate and a superstrate, which apply equal forces to each side of the filter. The present invention also includes an actively tunable thin film filter assembly, which utilizes stress applying devices, e.g. heaters or piezo-electric crystals, to adjust signal characteristics, such as the bandwidth, the group delay, and the chromatic dispersion, as desired.