IP Law Daily Fiber optic patent claims invalid as lacking sufficient written description
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Wednesday, May 10, 2017

Fiber optic patent claims invalid as lacking sufficient written description

By Jody Coultas, J.D.

The Patent Trial and Appeal Board erred in holding that certain claims of a fiber optic communications signal patent met the written description requirement, according to the U.S. Court of Appeals for the Federal Circuit. The Board, however, properly rejected a diverting element claims for lack of written description support (Cisco Systems, Inc. v. Cirrex Systems, LLC, May 10, 2017, Chen, R.).

U.S. Patent No. 6,415,082 (the ’082 patent) is directed to the field of fiber optic communication signals. Fiber optic communication signals use light energy made up of multiple different wavelengths within one fiber optic cable. To separate individual wavelengths from an optical beam, the ’082 patent describes an optical network assembly that uses a planar lightguide circuit (PLC). Claim 1 covers a cross-connect waveguide system. Optical waveguides are flexible fiber optic cables that can feed light signals away from or into a PLC. The ’082 patent originally issued with claims 1–34.

Cisco requested inter partes reexamination of all claims of the ‘082 patent. Cirrex added claims 35–124 during reexamination and subsequently amended and canceled several original claims. All 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 Examiner found claims 56, 57, 76, 102, and 103 patentable and rejected claims 38–41, 43–47, 49–50, 58–61, 75, 84–87, 89–93, 95–96, 104–107, and 121 for lack of written description. The Board affirmed. Cisco appealed the patentability finding for the equalization and discrete attenuation claims, while Cirrex appealed the rejection of the diverting element claims.

Claim construction. The court corrected the Board’s construction of "equalization" 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. Also, the court clarified that "discrete attenuation" did not encompass using the same attenuation element inside the PLC to attenuate all wavelengths of light in the same way.

Written description. The court reversed the Board’s finding of patentability of claims 56, 57, 76, 102, and 103. Patent claims meet the written description requirement where the disclosure reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date." Because none of the added claims were part of the ’082 patent’s original disclosure, Cirrex cannot rely on them for written description support. Under the correct claim construction for the equalization and discrete attenuation claims, there was no substantial evidence to support the Board’s finding that claims 56, 57, 76, 102, and 103 of the ’082 patent have sufficient written description support. The claims were directed to subject matter not included in the ’082 specification. The claims "cover a mechanism for acting on individual channels of light within the PLC to discretely attenuate one of several channels" or "a mechanism for acting on individual channels of light within the PLC to make their several intensities equal." The ’082 specification did not meet the quid pro quo required by the written description requirement for the disputed claims because demultiplexing light to manipulate separately the intensities of individual wavelengths of light while the light is still inside the PLC is a technically difficult solution that the ’082 specification does not solve, let alone contemplate or suggest as a goal or desired result.

Substantial evidence supported the Board’s finding of lack of written description support for the diverting element claims, according to the court. Cirrex cross-appealled the Board’s rejections of the diverting element claims for lack of written description support. The Board compared Figures 10 and 13 of the patent and found that both figures disclose a PLC and a separate element located outside the PLC, and that the ’082 specification does not provide for a separate embodiment with a diverting element inside the PLC. Therefore, the totality of the disclosure did not establish that the inventors possessed an embodiment with a diverting element inside the PLC. The court rejected Cirrex’s contention that the ’082 patent disclosed that the diverting element is inside the PLC, finding that the Board reasonably read the written description and figures in the ’082 patent.

The cases are Nos. 2016-1143 and 2016-1144.

Attorneys: David L. McCombs, Debra Janece McComas, Gregory P. Hus, and Julie Marie Nickols (Haynes & Boone, LLP) for Cisco Systems, LLC. Tarek N. Fahmi (Ascenda Law Group, PC) for Cirrex Systems, LLC.

Companies: Cisco Systems, LLC; Cirrex Systems, LLC

MainStory: TopStory Patent FedCirNews

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