Cisco Systems Inc v. Oyster Optics LLC

1. Case Identification

• Case #: IPR2021-00319
• Patent #: 6,665,500
• Filed: December 15, 2020
• Petitioner(s): Cisco Systems, Inc.
• Patent Owner(s): Oyster Optics, LLC
• Challenged Claims: 16

2. Patent Overview

• Title: Transmitters and Receivers for Fiber Optic Networks
• Brief Description: The ’500 patent discloses an optical transmission system featuring a transmitter capable of operating in dual modes. The system can transmit either amplitude-modulated optical signals or phase-modulated optical signals by switching between a first and second mode.

3. Grounds for Unpatentability

Ground 1: Obviousness over Gnauck and Hakki - Claim 16 is obvious over Gnauck in view of Hakki.

• Prior Art Relied Upon: Gnauck (Patent 5,303,079) and Hakki (Patent 6,549,311).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Gnauck teaches all elements of the claimed dual-mode optical transmission system except for a receiver explicitly including an interferometer. Gnauck discloses a lightwave transmission system with a transmitter that uses a Mach-Zehnder modulator to produce either pure amplitude-modulated signals or pure phase-modulated signals. According to the Petitioner, Gnauck’s controller achieves this by altering the drive voltages applied to the modulator’s electrodes—applying complementary (negative) signals for amplitude modulation and identical (in-phase) signals for phase modulation. This controller functionality meets the claim limitation of switching between a first mode (amplitude modulation) and a second mode (phase modulation) at different times. Gnauck further discloses the transmitter, laser, controller, and optical fiber elements of claim 16. To supply the final element, Petitioner asserted that Hakki teaches a receiver for phase-modulated signals that explicitly includes a Mach-Zehnder interferometer to recover telemetry information.
  • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would have been motivated to combine the teachings of the references. Because Gnauck’s transmitter can produce phase-modulated signals, a POSITA would have found it obvious to pair this transmitter with a receiver known to be capable of receiving such signals. Hakki provides a known and suitable solution by teaching an interferometer-based receiver for this exact purpose. The combination would have been a predictable implementation of known components to achieve a known result: creating a complete transmission system capable of operating in a phase-modulation mode.
  • Expectation of Success: Petitioner argued a POSITA would have had a reasonable expectation of success in combining the references. Implementing Hakki’s well-understood interferometer technology into Gnauck’s system to receive the phase-modulated signals Gnauck’s transmitter was designed to produce would have been a straightforward application of known principles.

4. Arguments Regarding Discretionary Denial

• Petitioner presented extensive arguments that discretionary denial under 35 U.S.C. §314(a) or §325(d) would be inappropriate. The core arguments asserted that the General Plastic and Fintiv factors weigh against denial. Petitioner emphasized that this was its first challenge to claim 16 and that a previous IPR on this claim filed by a different party (Infinera) was denied for discretionary reasons, not on the merits. Therefore, the Board had not previously considered the patentability of claim 16.
• Regarding the parallel district court litigation, Petitioner argued the case was in its very early stages with minimal investment from the parties and the court. It was also noted that the scheduled trial date was uncertain due to a crowded court docket and recent postponements, reducing the likelihood that a trial would conclude before a Final Written Decision (FWD) from the Board. Petitioner also stated that the prior art references and combination asserted in the petition were new and had not been considered during prosecution or in any prior IPR.

5. Relief Requested

• Petitioner requests the institution of an inter partes review (IPR) and the cancellation of claim 16 of the ’500 patent as unpatentable under 35 U.S.C. §103.