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Failure to Identify Internal Controls in Patent Specification Invalidates Patent Claims

The Court of Appeals for the Federal Circuit held that when a patent specification fails to explain where light channel controls are located (to discretely attenuate one of several light channels or to make their several intensities equal), the patent claim is indefinite under 35 U.S.C. sec. 112 and therefore invalid. Cisco Systems Inc. v. Cirrex Systems LLC, Case No. 2016-1143 (Fed. Cir. May 10, 2017) (Available Here).

This case arises from Cisco Systems, Inc.’s (Cisco) request for inter partes reexamination before the U.S. Patent and Trademark Office (USPTO) for the ‘082 patent, which is owned by Cirrex Systems, Inc. (Cirrex). During the reexam, Cirrex added a claim which the examiner rejected, finding that the claim limitations were not adequately explained in the patent specification. More precisely, the claim lacked written description support.

The ‘082 patent is directed to the field of fiber optic communication signals. The “single optical beam” comprises several different wavelengths, which “can include separate information channels that are carried by a first optical beam” having one particular wavelength and “a second optical beam” having a second particular wavelength. To separate individual wavelengths from an optical beam, the ‘082 patent describes an optical network assembly that uses a planar light guide circuit (PLC). The PLC, together with a series of filtering devices, splits the single, composite optical beam into multiple channels based on individual wavelengths.

These external optical waveguides can include amplifiers (which increase the intensity of the
light beam) and attenuators (which decrease the intensity of the light beam) to create optical systems that can perform equalization or discrete attenuation, and diverting elements (which can divert or introduce a light beam of a specific wavelength).

To modify an individual wavelength of light, the ‘082 patent describes using a “diverting element” outside the PLC to divert a light beam of wavelength and replace the beam with a different light beam of wavelength, then adding back into the PLC. The use of the illustrated cross-connect feedback loop allows a fiber optic communication system to transmit multiple channels of information on one fiber optic cable, without sacrificing the ability to manipulate the information being transmitted along each individual wavelength of light. This maximizes efficiency because multiple wavelengths of information can be sent simultaneously rather than having to be sent in seriatim.

The claim recites: A cross-connect waveguide system comprising: [a] a planar lightguide circuit having one or more optical paths; [b] a plurality of optical waveguides coupled to said planar lightguide circuit; [c] a plurality of filtering devices for feeding light energy into said optical paths of said planar lightguide circuit or receiving light energy from said optical paths of said planar lightguide circuit; and [d] a diverting element for feeding first light energy at a predetermined wavelength having first information content away from said planar lightguide circuit, and for feeding second light energy at said predetermined wavelength having second information content into said planar lightguide circuit, [e] wherein said diverting element is remotely configurable and is controlled with optically encoded information.

The problem for patentee Cirrex is that the ‘082 specification lacks any disclosure or suggestion of how placing attenuation material inside the PLC – which would necessarily impact the collective wavelengths in the PLC in the same way – would result in equalizing the intensities of different wavelengths traveling in the PLC, or discretely attenuating a particular wavelength in the PLC.
Stated otherwise, the patent specification failed to describe where the attenuation/equalization control element is located inside the planar light guide circuit (PLC).

The written description requirement provides that a patentee must “clearly allow persons of ordinary skill in the art to recognize that [he] invented what is claimed.” Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en bane) (quoting Vas-Cath Inc. v. Mahurkar, 935 F.2d 1555, 1563 (Fed. Cir. 1991)). “[T]he test for sufficiency is whether the disclosure of the application relied upon reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.” “[T]he level of detail required to satisfy the written description requirement varies depending on the nature and scope of the claims and on the complexity and predictability of the relevant technology.”

In Gentry Gallery, Inc. v. Berkline Corp., a patentee amended his claims to remove a limitation reciting the placement of controls for a set of two parallel recliners on a console between the two recliners. 134 F.3d 1473, 1479 (Fed. Cir. 1998). The Federal Circuit reversed the district court’s conclusion upholding the claims’ validity because the specification specifically contemplated the central console as the only location for the controls.

Per the Federal Circuit, “The claims are directed to subject matter that is indisputably missing from the ‘082 specification, i.e., 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.’”

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