Cisco Systems, Inc. v. Cirrex Systems, LLC

May 11, 2017

Federal Circuit No. 2016-1143, 2016-1144

Author: Thomas Negley

In Cisco Systems, Inc. v. Cirrex Systems, LLC (Fed. Cir. May 11, 2017), the Federal Circuit affirmed in part and reversed in part the Patent Trial and Appeals Board's decision in an inter partes reexamination proceeding, holding all claims unpatentable for lack of written description.  The claims related to a planar lightguide circuit (PLC) which performs various functions including, in a representative claim, an "equalization" function. 

The challenged claims recite that the equalization is performed inside the PLC.  Before the Board, both parties agreed that the equalization function occurs inside the PLC.  However, the Specification lacks any disclosure or suggestion of how placing attenuation material inside the PLC, which would necessarily impact the wavelengths in the PLC in the same way, would result in equalizing the intensities of different wavelengths traveling in the PLC.

Cirrex argued to the Board that the claimed “equalization” could refer to equalizing intensities of the wavelengths inside the PLC with respect to the intensity of a wavelength outside the PLC, rather than requiring that the equalization apply only to wavelengths inside the PLC.  The Board accepted this claim interpretation, and withdrew rejections for lack of written description.

On review, the Federal Circuit referred to Cirrex’s interpretation as “rather creative” and “out-of-the-box.”  The Federal Circuit reviewed the claim construction de novo, and found that the proper broadest reasonable interpretation required that the claimed functionality of equalization must occur inside the PLC with respect to the wavelengths traveling in the PLC, not to wavelengths outside of the PLC.  The Federal Circuit then found that the Specification did not meet the quid pro quo required by the written description requirement for the disputed claims because it did not support the broadest reasonable interpretation of the claims, and held all claims unpatentable for lack of written description.