On May 10, 2017 and following a Patent Trial and Appeal Board (PTAB) reexamination decision upholding certain claims, the United States Court of Appeals for the Federal Circuit ruled in Cisco Systems, Inc. v. Cirrex Systems, LLC that all of the appealed claims of a fiber optic patent held by Cirrex are invalid for lack of a written description support required by 35 U.S.C. § 112.  The panel applied its own construction of a key claim term requiring that a recited functional limitation take place in a specific location which the specification failed to describe.

In the reexamination, the PTAB affirmed the Examiner’s decision that while some of the claims were unpatentable “for lack of written description support,” others were valid.  The appellant, Cisco, appealed the PTAB’s holding that certain claims of U.S. Patent No. 6,415,082 (the “‘082 patent”), which Cisco had challenged as being unpatentable, were in fact patentable.  The ‘082 patent was originally asserted against Cisco in 2009 by Cirrex’s predecessor, Graywire, LLC, in the U.S. District Court for the Northern District of Georgia.  The district court stayed that case in 2009 pending the outcome of the reexamination proceeding.

The ’082 patent is directed to the field of fiber optic communication signals using light energy made up of multiple different wavelengths within one fiber optic cable.  The ‘082 patent describes that separating a “single optical beam” into its individual wavelength components allows operations such as adding or deleting, or changing the intensity of, the data signal carried to be performed selectively on specific wavelengths.  To separate individual wavelengths from an optical beam, the ’082 patent describes an optical network assembly that uses a planar lightguide circuit (PLC).  The PLC works together with a series of filtering devices to split the single optical beam into multiple channels based on individual wavelengths.  The PLC is also attached to external optical waveguides which can include amplifiers and attenuators to increase and decrease the intensity of the light beam resulting in systems that can perform equalization or discrete attenuation, and which can divert or introduce a light beam of a specific wavelength.

On appeal, the Federal Circuit panel analyzed the claims in three different groups as established by the parties: equalization claims, discrete attenuation claims, and diverting claims.  For each claim group, the panel determined that Cirrex failed to establish possession of any embodiment with the required elements.  Critical to that ultimate decision, the Federal Circuit determined that “[a]ll of the challenged claims recite that either equalization or discrete attenuation is performed inside the PLC, or that the diverting element is located inside the PLC.”  The parties had also agreed before the PTAB that both the equalization and discrete attenuation steps must occur while the light energy is traveling inside the PLC.

Ultimately, the Federal Circuit determined that the ’082 patent specification lacks any teaching directed to placing attenuation material inside the PLC to equalize the intensities of different wavelengths traveling or to discretely attenuate a particular wavelength in the PLC.  The panel rejected an argument by Cirrex that the recited equalization step could be fulfilled by equalizing the intensities of collective wavelengths inside the PLC with a wavelength that existed outside the PLC, noting that “noting in the specification describes such an embodiment” and that the equalization was required to take place as the wavelengths were traveling inside the PLC, which was not described by the specification.  The panel corrected the PTAB’s construction of the equalization and discrete attenuation claims to clarify that the individual wavelengths of light energy inside the PLC must be equalized with respect to other wavelengths of light energy while those wavelengths are traveling inside the PLC.  The panel also corrected the PTAB’s construction of the discrete attenuation claims to clarify differences between that and a collective approach to attenuation, consistent with the description in the ‘082 patent specification.

Addressing Cirrex’s cross appeal, the Federal Circuit affirmed the Board’s holding that the diverting element claims lacked written description support.  Cirrex’s argument that one of the patent figures showed that diverting element was flatly rejected.

In sum, the panel held that all of the claims added during the reexamination lacked written description support and could not be themselves relied upon since they were not part of the ’082 patent’s original disclosure.  The decision extends the Court’s 1998 Gentry Gallery holding that an original patent disclosure limits the permissible breadth of later-drafted claims.  As the panel stated, that earlier case stood for the “[u]nremarkable proposition that a broad claim is invalid when the entirety of the specification clearly indicates that the invention is of a much narrower scope.”  Applying that proposition to the challenged ‘082 patent claims added during reexamination, the panel determined that none could survive.