PTAB

IPR2017-01874

Cisco Systems Inc v. Oyster Optics LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Optical Fiber Communication System and Method
  • Brief Description: The ’511 patent discloses systems and methods for transmitting and receiving signals in a fiber optic network. While the specification focuses on security enhancements like optical time-domain reflectometers (OTDR) and tapping detection, the challenged claims are directed to the conventional method of operating an optical multiplexor that includes monitoring the average optical power of a received signal.

3. Grounds for Unpatentability

Ground 1: Claims 1-7 are obvious over Treyz in view of Ade, Hardcastle, Kobayashi, and Ikeda

  • Prior Art Relied Upon: Treyz (Patent 6,529,316), Ade (Patent 5,347,601), and Hardcastle (Patent 6,178,025).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Treyz disclosed an optical equipment card for a telecommunications system that includes a generic module for monitoring optical power. However, Treyz did not provide structural details for the transmitter/receiver components or the specific circuitry for the power monitor. Ade was cited to supply the well-known structure of an integrated optical transceiver (transmitter and receiver) that could be implemented as Treyz’s generic “optical equipment module.” Hardcastle was introduced to provide the specific, conventional circuitry for the power monitor itself, teaching a photodetector that converts a tapped optical signal to an electrical signal, which is then filtered by a low-pass filter to produce the claimed “average optical power.”
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Treyz and Ade to implement a complete transceiver on a single card, a known method for reducing system cost and complexity. As Treyz’s power monitor was described generically, a POSITA would have been motivated to look to a reference like Hardcastle to implement the specific and well-understood circuitry required to generate an average power signal, which was a predictable design choice.
    • Expectation of Success: The combination involved integrating known components (a transceiver and a power monitor circuit) into a known system architecture (an optical card), where each component performed its intended function to yield a predictable result.

Ground 2: Claims 9-15 are obvious over the combination for Ground 1 further in view of Hooijmans

  • Prior Art Relied Upon: Treyz (Patent 6,529,316), Ade (Patent 5,347,601), Hardcastle (Patent 6,178,025), and Hooijmans (a 1994 textbook, Coherent Optical System Design).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed independent claim 9, which adds the limitation that the optical signals are “phase-modulated.” Petitioner asserted that the primary combination of Treyz, Ade, and Hardcastle taught all elements of claim 9 except for the specific modulation scheme. Hooijmans, presented as a survey of known optical communication technologies, was cited for its disclosure of various modulation schemes, including phase-shift keying (PSK) and differential phase-shift keying (DPSK).
    • Motivation to Combine: The systems in Treyz and Ade were described as being applicable to various modulation schemes. A POSITA designing such a system would have found it obvious to select a suitable modulation technique from known options. Hooijmans taught that phase modulation provided known benefits, such as enabling higher data rates over longer transmission distances, motivating its use in the Treyz/Ade system.
    • Expectation of Success: Selecting and implementing a known modulation scheme into a conventional optical system was a routine design choice for a POSITA and would have yielded only predictable results and known benefits.

Ground 3: Claims 2-4 and 10-12 are obvious over the combinations for Grounds 1 and 2 further in view of Kobayashi

  • Prior Art Relied Upon: Treyz (Patent 6,529,316), Ade (Patent 5,347,601), Hardcastle (Patent 6,178,025), Hooijmans, and Kobayashi (Patent 6,404,281).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed dependent claims requiring “scaling the electrical signal after filtering with a...linear amplifier,” where the scaling is a function of expected optical power or fiber span length. Petitioner argued that while Hardcastle disclosed a basic amplifier, Kobayashi taught an improved transimpedance amplifier circuit specifically designed to scale a detected current to generate a voltage that is linearly proportional to the received optical power, even at high power levels.
    • Motivation to Combine: A POSITA implementing the power monitor taught by Hardcastle would have been motivated to improve its accuracy and linearity. Kobayashi addressed this exact problem by providing an improved, suitable amplifier. A POSITA would have also found it obvious to adjust the scaling factor (i.e., gain) of such a monitor based on the expected signal strength—which is a function of the fiber span length—to ensure that power fluctuations are easily detectable. This was a predictable design optimization.
    • Expectation of Success: Substituting Kobayashi’s improved linear amplifier for the generic amplifier in Hardcastle represented a simple substitution of one known element for another to obtain the predictable advantage of improved performance.
  • Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations using Corke (Patent 5,510,917) as an alternative primary reference to Treyz for a system with receiver-based power monitoring. Further grounds included Ikeda (Patent 7,016,612) to teach comparator circuits for claims 5-7 and 13-15. These alternative grounds relied on similar theories of combining known elements for their predictable functions.

4. Relief Requested

  • Petitioner requests institution of IPR for claims 1-7 and 9-15 of the ’511 patent and cancellation of those claims as unpatentable.