Cisco Systems, Inc. v. Oyster Optics, LLC

1. Case Identification

• Case #: Unassigned
• Patent #: 6,469,816
• Filed: June 30, 2017
• Petitioner(s): Cisco Systems, Inc. and Oclaro, Inc.
• Patent Owner(s): Oyster Optics, LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: Secure Optical Data Transmission System
• Brief Description: The ’816 patent discloses a fiber optic data transmission system intended to improve security against eavesdropping. The system uses phase modulation, specifically a differential phase shift keying (DPSK) technique, where a transmitter controller with a delayed-feedback exclusive-OR gate precodes an electronic data stream. This precoded signal then controls a phase modulator to alter the phase of a continuous wave laser, and a receiver uses an interferometer with a matched delay to decode the signal.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4, and 6 are obvious over Kaneda in view of Heflinger.

• Prior Art Relied Upon: Kaneda (Japanese Unexamined Patent Application Publication No. S61-127236) and Heflinger (Patent 6,396,605).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kaneda taught a complete DPSK system, including a transmitter with a laser, a phase modulator, and a controller using a delayed exclusive-OR (XOR) feedback loop. Kaneda also disclosed a receiver with an interferometer having two unequal light paths to decode the signal. However, Kaneda's interferometer was implemented in free space using mirrors and prisms. Heflinger taught an interferometer for a DPSK receiver where the optical paths are made of optical fiber. The combination of Kaneda's system with Heflinger’s fiber-based implementation allegedly supplied the "first fiber arm and a second fiber arm" limitation of independent claim 1.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because Heflinger provided a known, suitable alternative for implementing the interferometer in Kaneda's system. Petitioner asserted that using optical fiber was a well-known design choice that yielded predictable results and offered superior environmental stability and tolerance to vibration compared to Kaneda's free-space design.
  • Expectation of Success: A POSITA would have had a high expectation of success, as substituting optical fibers for a free-space path was a simple replacement of one known element for another to achieve a predictable improvement in stability.

Ground 2: Claims 7, 17, and 18 are obvious over Kaneda.

• Prior Art Relied Upon: Kaneda (Japanese Application S61-127236).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that independent method claim 7, unlike system claim 1, did not require the interferometer to have fiber arms. Therefore, Kaneda alone allegedly rendered these claims obvious. Kaneda disclosed all the recited method steps: receiving electronic input data, creating a control stream by combining the input data with delayed feedback data in an XOR circuit, using this stream to phase-modulate a continuous wave laser, and passing the resulting optical signal through a receiver interferometer with a delay matching the transmitter's feedback delay. Dependent claims 17 (feedback delay as a function of bit rate) and 18 (using an XOR gate) were also argued to be expressly taught by Kaneda's m-bit delay and "finite sum logic conversion circuit."

Ground 3: Claims 1, 4, 6 and others are obvious over Kaneda, Heflinger, and Alexander.

• Prior Art Relied Upon: Kaneda, Heflinger, and Alexander (Patent 5,726,784).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination of Kaneda and Heflinger to add the teachings of Alexander for claims requiring specific laser stability (e.g., dependent claims 2 and 3, limiting wavelength variance to <2 nm and <1 nm). Alexander taught a continuous wave laser for Wavelength Division Multiplexing (WDM) systems with a precise operating wavelength varying by only 0.1 nm.
  • Motivation to Combine: Petitioner argued a POSITA would be motivated to use a precise laser like Alexander's in the Kaneda system because Kaneda itself acknowledged the problem of "waveform distortion occurring due to effects of wavelength dispersion." Using a highly stable laser was a known solution to this known problem to improve the performance and fidelity of an optical communication system.
  • Expectation of Success: Modifying Kaneda's system with the stable laser from Alexander was a predictable substitution that would be expected to improve performance by reducing signal distortion.

Ground 4: Claims 5, 19, and 20 are obvious over Kaneda, Heflinger, and Corke.

• Prior Art Relied Upon: Kaneda, Heflinger, and Corke (Patent 5,510,917).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground added the teachings of Corke to the Kaneda/Heflinger combination to address limitations requiring a "tap detection monitor" or "energy level detector" (claim 5 and independent claim 19). Corke disclosed a system for monitoring an optical network by using a tap coupler to divert a portion of the signal to a detector, which monitored the signal's intensity (amplitude) to detect faults or performance degradation.
  • Motivation to Combine: A POSITA building the optical system of Kaneda/Heflinger would have been motivated to incorporate a performance monitoring system. Corke provided a known, conventional technique for monitoring optical signal levels to ensure network integrity. Adding this feature to the Kaneda system was merely the application of a known technique to a similar system to gain a known benefit.
  • Expectation of Success: A POSITA would have reasonably expected that adding a standard tap monitor to the receiver in Kaneda's system would successfully allow for the monitoring of signal energy levels with predictable results.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations of Kaneda, Alexander, and Corke (for claims 7-18) and a four-way combination of Kaneda, Heflinger, Alexander, and Corke (for claims 5, 19, and 20). These grounds relied on similar design modification theories to add features for wavelength stability and performance monitoring to different sets of base claims.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that the grounds asserted in this petition were not redundant with grounds in a concurrently filed IPR petition against the same patent. This petition's grounds relied on Kaneda, which is §102(b) prior art, while the other petition relied on Bauch (Patent 6,826,371), which is §102(e) prior art. Petitioner contended that because the references have different prior art statuses, the Patent Owner may have different available defenses (e.g., swearing behind Bauch but not Kaneda), making the grounds distinct.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of Patent 6,469,816 as unpatentable under 35 U.S.C. §103.