In Cisco Systems, Inc. v. Cirrex Systems, LLC, [2016-1143, 2016-1144](May 10, 2017), the Federal Circuit affirmed in part, and reversed in part the Board’s decision in Inter Partes Reexamination of U.S. Patent No. 6,415,082.  Cisco appealed the patentability finding of five of the claims, and Cirrex appealed the rejection of the remainder of the claims.  The Federal Circuit found that all of the claims on appeal were unpatentable for lack of written description support.

The ‘082 patent is directed to the field of fiber optic communication signals.  At issue was the claim requirement of discrete attenuation of the various wavelengths of light, which the parties agreed must occur in the planar lightguide circuit (PLC).  However, there was not written description of how discrete attenuation could occur within the PLC, rather that attenuation of all of the wavelengths (i.e. collective attenuation).  The Federal Circuit agreed with Cisco that the claims are directed to subject matter that is indisputably missing from the ’082 specification.

The Federal Circuit said that the ’082 specification does 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.  The Federal Circuit added:

Nothing in the ’082 specification explains how individual wavelengths of light are separately manipulated while those wavelengths are still inside the PLC. Nor is there anything in the specification that suggests that the inventor contemplated that approach. To the contrary, the ’082 specification expressly describes using the PLC to separate wavelengths of light to allow the manipulation of each individual wavelength — outside the PLC — before it is rerouted back into the PLC for remultiplexing.

The Board also rejected Cirrex’s arguments that the claims requiring a diverting element were supported by adequate written description.  The Board concluded that the totality of of the disclosure did not establish that the inventors possessed an embodiment with a diverting element inside the PLC, and the Federal Circuit agreed.