PTAB

IPR2017-02109

Halliburton Energy Services Inc v. United States

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Natural Fiber Span Reflectometer Providing a Virtual Signal Sensing Array Capability
  • Brief Description: The ’971 patent describes a time-domain reflectometer system for sensing external physical signals (e.g., acoustic waves) along an optical fiber span. The system uses a pseudo-random coded light signal, a heterodyne optical receiver to detect naturally occurring backscatter, and a programmable correlator to create a virtual sensor array.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 6, 12, 14, 15, and 18-22 by Everard

  • Prior Art Relied Upon: Everard (UK Patent Application No. GB 2 190 186 A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Everard discloses every element of the challenged claims. Everard describes a distributed fiber optic sensor system that uses a continuous wave (CW) laser modulated by a pseudo-random bit sequence (PRBS). This modulated signal is launched into an optical fiber, and the backscattered signal is mixed with a frequency-shifted local oscillator signal at a photodetector (a heterodyne receiver) to detect changes caused by external parameters. Petitioner argued Everard’s system is a time-domain reflectometer for sensing along a fiber span, using a modulated signal and a heterodyne receiver to analyze backscatter, thus anticipating the independent claims. For dependent claims, Petitioner argued Everard discloses using lasers that retain coherency (claim 6), using a photodetector-type heterodyner (claim 12), and using shift registers to generate the PRBS (claim 15).
    • Key Aspects: The core of this ground is that Everard, which was not considered during prosecution, teaches a complete heterodyne-based, correlation-type reflectometer that performs the same function as the ’971 patent’s invention.

Ground 2: Obviousness of Claims 1-3, 6-10, 12, 14, and 18-22 over Kersey in view of Yoshino or Beckmann

  • Prior Art Relied Upon: Kersey (Patent 6,285,806), Yoshino (Journal of Lightwave Technology, Apr. 1992), and Beckmann (Patent 4,794,249).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Kersey discloses a fiber optic sensing system using a PRBS-modulated light source, an optical fiber with multiple sensing segments, and a set of correlators to determine phase shifts at different locations. While Kersey teaches the core system, it does not explicitly detail a heterodyne receiver. Yoshino and Beckmann both disclose heterodyne detection systems for use in fiber optic sensing. Yoshino teaches a differential heterodyne sensor using a phasemeter to detect beat signals, and Beckmann teaches an optical time-domain reflectometer (OTDR) using heterodyne reception with a local oscillator laser to improve signal evaluation. Petitioner contended that combining Kersey’s system with the heterodyne receiver taught by either Yoshino or Beckmann would render the claims obvious.
    • Motivation to Combine: A person of ordinary skill in the art (POSA) would have been motivated to incorporate a heterodyne receiver into Kersey’s system because Kersey itself explicitly suggests using heterodyne processing to improve performance. Furthermore, heterodyne detection was a well-known technique for increasing signal-to-noise ratio, stability, and accuracy in fiber optic sensing systems.
    • Expectation of Success: Combining these known elements was straightforward. A POSA would have understood that integrating a known heterodyne receiver (from Yoshino or Beckmann) into a known correlation-based reflectometer system (from Kersey) was a predictable implementation that would successfully yield the known benefits of heterodyne detection.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Everard with secondary references to teach specific features, such as using a single-mode fiber (in view of Fredin, Patent 6,606,148), a balanced optical detector (in view of Wright, Patent 4,596,052), or a specific phase demodulator (in view of Payton ’921, Patent 6,043,921). Further grounds combined Kersey/Yoshino/Beckmann with tertiary art for similar reasons.

4. Key Claim Construction Positions

  • "lightwave heterodyner" (Claim 1): Petitioner proposed this term be construed as a “near-ultraviolet to mid-infrared wavelength-sensitive detector with inputs of differing wavelengths and an output providing the difference between the input wavelengths.” This broad, functional construction is argued to be supported by the specification’s contrast between heterodyne (non-zero frequency difference) and homodyne (zero frequency difference) detection and is not limited to a specific structure. This construction allows the photodetector arrangements in Everard, Yoshino, and Beckmann to meet the claim limitation.
  • "in phase locked relation" / "in phase locked synchronism" (Claims 1, 21, 22): Petitioner argued this phrase should be construed as “related in phase,” referring to a state or relationship rather than requiring specific phase-locking circuitry. The specification describes an alternative embodiment where a Bragg cell shifts a portion of light from a single laser, creating a second signal that is inherently in a phase-locked relation. This construction allows systems like Everard’s, which use frequency shifting, to meet the limitation without dedicated locking circuitry.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review for claims 1-3, 6-16, and 18-22 of the ’971 patent on all asserted grounds and the cancellation of these claims as unpatentable.