PTAB

IPR2015-00726

Fujitsu Network Communications Inc v. Capella Photonics Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Wavelength Selective Switch and an Optical Add-Drop Multiplexer Using Same
  • Brief Description: The ’368 patent discloses a wavelength selective switch (WSS) for use in optical add-drop multiplexers (OADMs) within wavelength division multiplexing (WDM) fiber-optic networks. The technology uses a spatial array of beam-deflecting elements, such as MEMS mirrors, to individually route and control the power of different spectral channels of light.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 1-6, 9-12, and 15-22 are anticipated by Smith

  • Prior Art Relied Upon: Smith (Patent 6,798,941).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Smith, which was not before the Patent Office during prosecution, discloses every limitation of the challenged claims. During reissue, the Patent Owner amended the claims to add limitations requiring that the beam-deflecting elements be controllable in two dimensions to control the power of spectral channels. Petitioner contended that Smith explicitly teaches a MEMS mirror array where each mirror is individually and continuously controllable in two dimensions to both reflect a channel to a selected port and to control the power of that channel via intentional misalignment. Smith also allegedly discloses the servo-control assembly with feedback control recited in dependent claims 3 and 4.

Ground 2: Obviousness over Bouevitch in view of Carr - Claims 1, 2, 5, 6, 9-12, and 15-21 are obvious

  • Prior Art Relied Upon: Bouevitch (Patent 6,498,872) and Carr (Patent 6,442,307).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Bouevitch, a primary reference from the reissue prosecution, discloses a configurable OADM with all claimed elements except for beam-deflecting elements that are controllable in two dimensions for power control; Bouevitch’s mirrors operate on a single axis. Carr allegedly remedies this deficiency by disclosing a two-dimensional array of double-gimbaled MEMS mirrors that can be tilted about two perpendicular axes to any desired orientation. Carr further teaches using this two-axis control for power attenuation by intentionally misaligning the mirror to control the portion of the reflected signal that enters an output fiber.
    • Motivation to Combine: A POSITA would combine the references because they address the same problem in the same field (optical switching in WDM systems) using similar MEMS-based technology. Petitioner argued it would have been an obvious and predictable substitution to replace Bouevitch’s one-axis mirrors with Carr’s known two-axis mirrors to improve the system, such as by better compensating for alignment errors arising from assembly or temperature changes. This combination was presented as the use of a known technique (two-axis mirrors from Carr) to improve a similar device (the OADM of Bouevitch).
    • Expectation of Success: A POSITA would have had a high expectation of success because implementing two-axis mirrors instead of one-axis mirrors was one of a small number of predictable design choices, and the effect of tilting a mirror in two dimensions to steer a light beam was well understood.

Ground 3: Obviousness over Bouevitch in view of Sparks - Claims 1-4, 17, and 22 are obvious

  • Prior Art Relied Upon: Bouevitch (Patent 6,498,872) and Sparks (Patent 6,625,340).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground is similar to Ground 2, using Sparks as the secondary reference to supply the limitations missing from Bouevitch. Petitioner argued that Sparks discloses an optical switch with MEMS mirrors capable of two-axis movement. Sparks explicitly teaches that this two-axis movement is used to deliberately misalign the optical beam path to attenuate the signal and achieve a desired output power. Critically, Sparks also discloses a closed-loop servo-control system that measures optical power and controls the mirrors to maintain predetermined power levels, directly corresponding to the limitations of dependent claims 3 and 4.
    • Motivation to Combine: The motivation to combine was substantially similar to that for combining Bouevitch and Carr: improving the Bouevitch OADM with known, advantageous technology from Sparks. A POSITA would be motivated to incorporate Sparks’ two-axis mirrors for improved beam steering and its integrated servo-control system to achieve more precise, automated power control without needing external components, a known issue in the art.
    • Expectation of Success: The expectation of success was high due to the predictable nature of combining known components (two-axis mirrors, servo-control systems) common in the field of optical switching to achieve their known functions.

  • Additional Grounds: Petitioner asserted additional obviousness grounds by adding Tew (Application # 2002/0081070) to the primary combinations (Smith in view of Tew; Bouevitch in view of Carr and Tew; Bouevitch in view of Sparks and Tew). These grounds were presented to the extent the Board found the primary references did not adequately disclose the "continuously controllable" limitation. Tew was cited for its explicit teaching of using analog voltage for continuous, non-discrete control of micromirrors to provide fine control over attenuation.

4. Key Claim Construction Positions

Petitioner argued for the following constructions under the broadest reasonable interpretation standard, contending they are critical to the invalidity analysis:

  • "in two dimensions": Proposed construction is "in two axes." Petitioner argued the specification consistently describes the beam-deflecting mirrors as tilting or pivoting about two axes to deflect light.
  • "continuously controllable": Proposed construction is "under analog control." Petitioner cited specification language stating that a "distinct feature" of the invention is that the mirror motion is under "analog control" so its pivoting angle can be "continuously adjusted."
  • "beam-deflecting elements": Proposed construction is "moveable mirrors." The specification is said to describe these elements as "micromachined mirrors" or "reflective ribbons (or membranes)."
  • "servo-control assembly": Proposed construction is "assembly that uses automatic feedback to control a device in response to a control signal." Petitioner argued the specification equates servo control with using a spectral monitor to provide "feedback" for controlling the mirrors.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-6, 9-12, and 15-22 of the ’368 patent as unpatentable.