US 8441721

US patent 8441721, titled "System and method of Raman amplifier pump control," was issued on May 14, 2013, from an application filed on December 30, 2009. The patent was originally assigned to Alcatel Lucent SAS and is currently assigned to WSOU Investments LLC. The sole inventor listed is Christopher Alan White.

Abstract:
The patent describes a method for controlling Raman amplification. It involves receiving power measurements for multiple optical channels and creating deviation measurements by comparing these to target power levels. Correctable deviations are then determined by projecting the measured deviations into a space that defines achievable Raman gain profiles. Finally, pump settings for the Raman pumps are determined based on these correctable deviations by solving an optimization problem. These pump settings can then be applied to the pumps.

Independent Claims Overview:

• Claim 1 (Method): This claim describes a method for controlling Raman amplifier pumps. It involves four key steps:

  1. Receiving measured channel powers: Obtaining data on the power levels of optical channels.
  2. Determining deviations: Calculating the difference between the measured channel powers and their desired (target) power levels.
  3. Projecting deviations: Taking these deviations and mathematically mapping them into a specific "space" that represents the Raman gain profiles that can actually be achieved by adjusting the pump lasers. This step results in "projected deviations."
  4. Determining power settings: Calculating the new power settings for the pump lasers based on these "projected deviations."

• Claim 9 (Method): This claim also describes a method focused on optimizing Raman pump settings, specifically by:

  1. Removing uncorrectable features: Identifying and excluding any aspects of the measured power deviations that cannot be fixed by adjusting the Raman pumps.
  2. Optimizing power settings: Using the remaining "correctable changes" (the deviations after the uncorrectable features have been removed) to determine optimal power settings for the Raman pumps.

• Claim 13 (Method): This method claim outlines a process for determining pump settings:

  1. Receiving power measurements: Getting power data for multiple optical channels.
  2. Creating deviation measurements: Calculating the difference between measured powers and target powers for each channel.
  3. Determining correctable deviations: Identifying the portion of these deviation measurements that can be corrected by Raman pump adjustments, effectively partitioning the total deviations into correctable and non-correctable parts.
  4. Determining pump setting: Calculating the pump settings for a plurality of pumps based on these identified correctable deviations.

• Claim 19 (Apparatus): This claim describes an apparatus (specifically, a processor) configured to perform the steps of Claim 1. The processor is set up to:

  1. Receive measured channel powers.
  2. Determine deviations from target channel powers.
  3. Project these deviations into the space of achievable Raman gain profiles to form projected deviations.
  4. Determine pump laser power setting values based on these projected deviations.

• Claim 20 (Non-transitory computer readable medium): This claim covers a non-transitory computer readable medium (e.g., a hard drive or flash memory) storing machine-executable code. When a processor executes this code, it performs the method steps substantially similar to Claim 13:

  1. Receiving power measurements for optical channels.
  2. Creating deviation measurements.
  3. Determining correctable deviations (as a correctable portion of total deviations).
  4. Determining pump settings based on these correctable deviations.

• Claim 23 (Apparatus): This claim describes an apparatus (a processor) configured to carry out the method of Claim 9. The processor is configured to:

  1. Remove features from measured deviations that cannot be corrected by Raman pump adjustments.
  2. Optimize power setting values for the Raman pumps based on the remaining "space of correctable changes."

• Claim 24 (Apparatus): This claim describes an apparatus including a processor and an associated memory unit, configured to perform the method steps of Claim 13:

  1. Receive power measurements for optical channels.
  2. Create deviation measurements.
  3. Determine correctable deviations (as a correctable portion of total deviations).
  4. Determine pump settings based on these correctable deviations.

Litigation and Legal Status:
The patent's legal status is "Expired - Fee Related," specifically lapsing on June 21, 2021, due to failure to pay maintenance fees. An adjusted expiration date of October 9, 2031, is noted, but the patent formally expired earlier due to non-payment.

Despite its expired status, the patent has been involved in recent litigation:

• A PTAB case, IPR2025-00241, was filed (Settlement). The opponent name for this IPR is CISCO SYSTEMS, INC., and the effective date was December 2, 2024.
• A US case was filed in the Texas Eastern District Court, case number 2:24-cv-00332.
• There is also a record of the first worldwide family litigation filed.

As of April 26, 2026, a search for CAFC 2026 dockets specifically for US8441721 did not yield any direct results indicating an appeal has reached the Court of Appeals for the Federal Circuit for this patent during 2026.US patent 8441721, titled "System and method of Raman amplifier pump control," was issued on May 14, 2013, from an application filed on December 30, 2009. The patent was originally assigned to Alcatel Lucent SAS and is currently assigned to WSOU Investments LLC. The sole inventor listed is Christopher Alan White.

Abstract:
The patent describes a method for controlling Raman amplification. It involves receiving power measurements for multiple optical channels and creating deviation measurements by comparing these to target power levels. Correctable deviations are then determined by projecting the measured deviations into a space that defines achievable Raman gain profiles. Finally, pump settings for the Raman pumps are determined based on these correctable deviations by solving an optimization problem. These pump settings can then be applied to the pumps.

Independent Claims Overview:

• Claim 1 (Method): This method involves:

  1. Receiving measured power levels for optical channels.
  2. Calculating the difference (deviations) between these measured powers and their target power levels.
  3. Projecting these deviations into a mathematical "space" that represents the Raman gain profiles that can actually be achieved by adjusting the pump lasers, resulting in "projected deviations."
  4. Determining the power setting values for the pump lasers based on these projected deviations.

• Claim 9 (Method): This method focuses on optimizing Raman pump settings by:

  1. Identifying and removing any aspects of the measured power deviations that cannot be corrected by adjusting the Raman pumps.
  2. Optimizing the pump power setting values based only on the remaining "correctable changes" (the deviations after the uncorrectable features have been removed).

• Claim 13 (Method): This method outlines a process for determining pump settings:

  1. Receiving power measurements for a plurality of optical channels.
  2. Creating deviation measurements by finding the difference between these measurements and corresponding target power levels.
  3. Determining the "correctable deviations" for these channels, which are identified as the portion of the total deviation measurements that can be corrected, effectively partitioning the deviations.
  4. Determining a pump setting for a plurality of pumps based on these correctable deviations.

• Claim 19 (Apparatus): This claim describes an apparatus comprising a processor that is configured to perform the steps of Claim 1. Specifically, the processor is set up to receive measured channel powers, determine deviations from target powers, project these deviations into the space of achievable Raman gain profiles, and then determine pump power setting values based on the resulting projected deviations.

• Claim 20 (Non-transitory computer readable medium): This claim covers a non-transitory computer readable medium (e.g., software or firmware) that stores machine-executable code. When executed by at least one processor, this code causes the processor to perform steps similar to Claim 13: receive power measurements, create deviation measurements, determine correctable deviations (as a correctable portion of total deviations), and determine pump settings based on these correctable deviations.

• Claim 23 (Apparatus): This claim describes an apparatus comprising a processor configured to perform the method of Claim 9. The processor is configured to remove uncorrectable features from measured deviations and then optimize pump power setting values based on the remaining correctable changes.

• Claim 24 (Apparatus): This claim describes an apparatus with a processor and associated memory unit, configured to perform the method steps of Claim 13: receive power measurements, create deviation measurements, determine correctable deviations (as a correctable portion of total deviations), and determine pump settings based on these correctable deviations.

Litigation and Legal Status:
US patent 8441721 is currently in "Expired - Fee Related" status, having lapsed on June 21, 2021, due to the failure to pay maintenance fees. An adjusted expiration date of October 9, 2031, is noted, but the patent formally expired earlier due to non-payment.

Despite its expired status, the patent has been involved in recent litigation:

• A PTAB (Patent Trial and Appeal Board) case, IPR2025-00241, was filed (Settlement) by Petitioner CISCO SYSTEMS, INC., with an effective date of December 2, 2024.
• A US district court case, 2:24-cv-00332, was filed in the Texas Eastern District Court.
• The patent family has also been involved in its first worldwide litigation.

As of April 26, 2026, a search for CAFC (Court of Appeals for the Federal Circuit) 2026 dockets specifically for US8441721 did not return any direct results, meaning there is no publicly available record of an appeal for this patent having reached the CAFC in 2026.