PTAB

IPR2018-00984

Nokia Of America Corp v. Oyster Optics LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Optical Fiber Data Transmission System
  • Brief Description: The ’952 patent discloses a fiber optic data transmission system designed for enhanced security against eavesdropping. The system employs differential phase shift keying (DPSK) modulation, where the phase of a light signal is altered based on both the current input data bit and a previously encoded bit, making the signal more difficult to decode without a matching receiver.

3. Grounds for Unpatentability

Ground 1: Obviousness over Kaneda and Schneider - Claims 1-3 and 5 are obvious over Kaneda in view of Schneider.

  • Prior Art Relied Upon: Kaneda (Japanese Application # S61-127236) and Schneider (Patent 6,700,907).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kaneda disclosed the fundamental architecture of a DPSK optical communication system. This included a transmitter with a laser, a phase modulator, and a control circuit performing an exclusive-OR (XOR) function with a time delay, paired with a receiver containing a corresponding interferometer. However, Kaneda lacked specific details on how to implement and control the phase modulator for stable operation. Schneider allegedly supplied these missing details by teaching a robust control circuit for a Mach-Zehnder (MZ) modulator. Schneider's circuit used a microcontroller and a digital-to-analog converter (DAC) to apply a DC bias voltage, thereby altering the modulator's phase to compensate for environmental noise, temperature changes, and component aging. Petitioner contended that the combination of Kaneda's system architecture with Schneider's control circuitry met all limitations of independent claim 1. Dependent claims were met because Kaneda's XOR circuit was best implemented with a feedback loop (claim 2), its receiver interferometer inherently imparted a 180-degree phase shift for DPSK decoding (claim 3), and Schneider’s control algorithm adjusted phase using predetermined increments, functioning as a phase-compensation circuit (claim 5).
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Schneider's well-known modulator control system with Kaneda's DPSK system to achieve predictable, stable, and long-term operation. Petitioner asserted this was a simple substitution of a known, superior component (a precisely controlled MZ modulator) into an existing system architecture (Kaneda) to solve the widely recognized problem of modulator drift.
    • Expectation of Success: The combination involved applying a standard control circuit from Schneider to a standard modulator type used in a known communication scheme taught by Kaneda. As this involved integrating known solutions for known problems, a POSITA would have had a high expectation of success.

Ground 2: Obviousness over Kaneda, Schneider, and Heflinger - Claim 4 is obvious over Kaneda and Schneider in view of Heflinger.

  • Prior Art Relied Upon: Kaneda (Japanese Application # S61-127236), Schneider (Patent 6,700,907), and Heflinger (Patent 6,396,605).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination asserted in Ground 1 and addressed the additional limitation of claim 4, which depends from claim 3 and requires the receiver's interferometer to include an "additional phase modulator" in at least one of its arms. Petitioner argued that Kaneda's free-space interferometer was susceptible to performance degradation from temperature variations. Heflinger was cited as teaching a solution to this exact problem by disclosing an interferometer with a tuning mechanism. Specifically, Heflinger taught using a piezoelectric transducer (PZT) to physically adjust the position of mirrors within an interferometer, thereby altering the optical path length and, consequently, the phase in that arm. This PZT, controlled by a feedback loop to maintain optimal performance, functioned as the claimed "additional phase modulator."
    • Motivation to Combine: A POSITA implementing the system of Kaneda and Schneider would recognize the known problem of thermal instability in Kaneda's free-space interferometer. Heflinger directly addressed this problem for DPSK demodulators. Therefore, a POSITA would be motivated to incorporate Heflinger's PZT-based tuning system into the receiver of the combined Kaneda/Schneider system to improve its robustness and reliability in real-world operating conditions.
    • Expectation of Success: Adding a known tuning mechanism from Heflinger to a standard interferometer as disclosed in Kaneda to solve the known problem of thermal drift was presented as a straightforward and predictable design choice, leading to a high expectation of success.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-5 of Patent 6,476,952 as unpatentable under 35 U.S.C. §103.