PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT

PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT
This memorandum is protected by the attorney-client privilege and/or the work product doctrine. It is intended solely for the use of the addressee and other attorneys and staff of Calderwood & Harkness LLP working on the above-referenced matter. Any unauthorized disclosure, distribution, or copying of this memorandum or the information contained herein is strictly prohibited.
MEMORANDUM
TO: Alan Ngo, Responsible Partner, Calderwood & Harkness LLP
FROM: Christy Bauer, Associate, intellectual Property Group, Calderwood & Harkness LLP Omar Siddiqui, Lead Associate, intellectual Property Group, Calderwood & Harkness LLP
DATE: September 19, 2022
RE: Proposed ESI Search Terms and Custodian List — Optiwave Semiconductor Corp. v. Lumos Photonics, Inc., Case No. 5:22-cv-03417-EJD (N.D. Cal.)
MATTER NUMBER: 1014-00003
CLIENT: Optiwave Semiconductor Corp. ("OWS")
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I. Purpose and Scope
This memorandum sets forth the proposed custodian list and electronically stored information ("ESI") search methodology for OWS's document collection, review, and production in the above-captioned patent infringement action. The recommendations contained herein are intended to facilitate a comprehensive, defensible, and cost-effective approach to OWS's discovery obligations under the Federal Rules of Civil Procedure and the Northern District of California's Patent Local Rules.
As background, a litigation hold notice was distributed to relevant OWS personnel on June 1, 2022, directing preservation of all potentially relevant ESI across OWS's corporate systems, including email, network file shares, engineering design repositories, and personal devices used for business purposes. That litigation hold notice identified the key subject matters and time periods for preservation and instructed recipients to suspend any routine document destruction or auto-deletion protocols for materials falling within its scope. The litigation hold remains in effect and will continue through the resolution of this matter.
The parties exchanged initial disclosures on August 22, 2022, pursuant to Federal Rule of Civil Procedure 26(a)(1). The Initial Case Management Conference was held on August 15, 2022, before the Honorable Edward J. Torvelis of the United States District Court for the Northern District of California. At that conference, the Court set an initial case schedule and directed the parties to meet and confer regarding the scope and format of ESI discovery.
Preliminary claim construction contentions were served by both parties on September 12, 2022, pursuant to Patent Local Rule 4-1. The claim-construction-related discovery period will close on October 31, 2022, necessitating an accelerated collection and review timeline for documents bearing on claim construction issues, including prosecution history materials, inventor testimony support documents, and technical documents relevant to the meaning of disputed claim terms.
We anticipate that Lumos Photonics, Inc. ("Lumos") will serve its first set of document requests in early November 2022. Based on our discussions with defense counsel at Brannick Howell & Stein LLP ("BHS"), we expect that these requests will be extensive, potentially numbering in excess of ninety requests, and will cover the full range of infringement, validity, damages, and prosecution history topics typical of a multi-patent case of this nature. (Lumos ultimately served 98 requests for production on November 7, 2022.) In parallel, OWS has its own affirmative production obligations and must ensure that its document collection captures all materials that OWS may need to use in support of its own infringement contentions, damages theories, and claim construction positions.
The Stipulated Protective Order governing materials designated as "Confidential" and "Highly Confidential — Attorneys' Eyes Only" was entered by the Court in September 2022. All productions in this matter will be governed by the terms of that order, and confidentiality designations will be applied at the document level during the review process.
This memorandum does not address the detailed privilege review workflow, document coding guidelines, or quality control procedures for the substantive document review. Those topics will be addressed in a separate Document Review Protocol Memorandum, which is targeted for issuance in November 2022, prior to the commencement of the principal merits-discovery document review. The present memorandum focuses on (a) the identification of custodians, (b) the formulation of search terms, (c) the collection protocol, and (d) the projected timeline and budget for the ESI effort.
II. Factual Background Relevant to ESI Scope
To provide context for the custodian selections and search term formulations discussed below, we briefly summarize the key factual and technical background of this case.
A. The Patents-in-Suit
OWS has asserted four United States utility patents against Lumos in this action. Each patent relates to a different aspect of silicon photonics technology used in high-speed optical transceivers for data center interconnect and telecommunications applications. The four patents-in-suit are:
1.  U.S. Patent No. 10,234,567 (the "'567 Patent") — Entitled "Integrated Waveguide Coupler with Tapered Mode Converter for Silicon Photonics Platforms." The '567 Patent was filed on March 14, 2017, and issued on March 19, 2019. The named inventors are Dr. Kevin Fong, Dr. Priya Ramanathan, and Hideo Tanaka. This patent claims an integrated waveguide coupling structure featuring an adiabatically tapered mode converter that enables efficient optical power transfer between a silicon waveguide and a III-V gain medium on a silicon photonics platform. The '567 Patent is central to OWS's theory that Lumos's accused products utilize a waveguide coupling architecture that falls within OWS's claimed design.
2.  U.S. Patent No. 10,891,234 (the "'234 Patent") — Entitled "Germanium-on-Silicon Photodetector with Graded Buffer Layer for Enhanced Responsivity." The '234 Patent was filed on September 8, 2017, and issued on January 14, 2021. The named inventors are Dr. Kevin Fong and Dr. Amara Osei. This patent claims a germanium photodetector structure fabricated on a silicon substrate using a graded buffer layer with a continuously varying germanium concentration profile, achieving enhanced optical responsivity at telecommunications wavelengths. The key claim construction dispute centers on the meaning of "continuously varying germanium concentration" as distinguished from step-graded approaches.
3.  U.S. Patent No. 11,045,678 (the "'678 Patent") — Entitled "Multi-Channel Optical Transceiver with Integrated Wavelength-Division Multiplexing on Silicon." The '678 Patent was filed on June 22, 2018, and issued on June 29, 2021. The named inventors are Dr. Priya Ramanathan, Dr. Amara Osei, and Liwei Zhang. This patent claims a multi-channel optical transceiver in which the wavelength-division multiplexing (WDM) components — including arrayed waveguide gratings and microring resonators — are monolithically formed on a single silicon die together with the transmitter and receiver elements. A central construction dispute involves whether "monolithically formed" excludes heterogeneous integration techniques such as micro-transfer printing or flip-chip bonding.
4.  U.S. Patent No. 11,312,890 (the "'890 Patent") — Entitled "Driver Circuit Architecture for High-Speed Silicon Photonic Mach-Zehnder Modulators." The '890 Patent was filed on November 15, 2018, and issued on April 26, 2022. The named inventors are Dr. Kevin Fong and Rajesh Iyer. This patent claims a driver circuit architecture for Mach-Zehnder modulators (MZMs) in which a pre-emphasis equalization stage is electrically co-integrated with the modulator on a common substrate, enabling high-speed modulation at data rates exceeding 100 Gbaud per lane. The '890 Patent is the most recently issued of the four asserted patents and is relevant to OWS's infringement theory concerning the modulation driver subsystem within Lumos's accused products.
B. Accused Products
OWS's Complaint alleges that two Lumos products infringe one or more claims of the patents-in-suit:
•  LumosBridge™ 800G Optical Engine: A co-packaged optics (CPO) module designed for integration with next-generation network switches in hyperscale data centers. The LumosBridge product is alleged to incorporate infringing waveguide coupler, photodetector, WDM, and modulator driver technologies corresponding to all four patents-in-suit.
•  LumosEdge™ 400ZR+ Pluggable Transceiver: A QSFP-DD form factor coherent pluggable transceiver module for data center interconnect (DCI) applications at distances up to 120 kilometers. The LumosEdge product is alleged to infringe claims of the '567 Patent, the '234 Patent, and the '890 Patent.
C. Key Technical Subject Areas
The technical subject matter implicated by the four patents-in-suit and the accused products spans several interrelated areas of silicon photonics technology:
•  Waveguide coupling and tapered mode converters: The design and fabrication of optical coupling structures that transfer light between waveguides of different geometries or materials, including adiabatic taper designs.
•  Germanium photodetectors and graded buffer layers: The fabrication of germanium-on-silicon photodetectors using epitaxially grown buffer layers with controlled germanium concentration profiles to manage lattice mismatch and enhance device performance.
•  Wavelength-division multiplexing and monolithic integration: The integration of WDM multiplexer and demultiplexer components (arrayed waveguide gratings, microring resonators) on a common silicon die with active photonic elements, as distinguished from hybrid or heterogeneous integration approaches.
•  Mach-Zehnder modulator driver circuits and co-integration: The design of electronic driver circuits optimized for silicon photonic MZM structures, particularly architectures in which the driver electronics and the optical modulator are co-integrated on a shared substrate.
D. OWS's Business Context
OWS is a fabless semiconductor design company incorporated in Delaware and headquartered in San Jose, California. OWS designs silicon photonics integrated circuits for high-speed optical communications applications and has its chips fabricated by Pinnacle Semiconductor Foundry Co., Ltd. ("Pinnacle") on a 45nm silicon-on-insulator (SOI) process. OWS's key commercial products include the OWS-400ZR and OWS-800LR coherent optical transceiver chipsets, which are sold to optical module manufacturers and system integrators serving the data center interconnect and telecommunications markets.
OWS holds a substantial intellectual property portfolio consisting of 87 issued U.S. utility patents and 14 pending patent applications, all relating to silicon photonics technology. The four patents-in-suit represent a core subset of this portfolio directed to what OWS considers its foundational innovations in waveguide coupling, photodetection, WDM integration, and modulator driver design.
OWS is a privately held company. Its majority shareholder is Vantage Point Capital Partners II, L.P. ("VPCP"), a venture capital fund. OWS maintains a $40 million revolving credit facility with First Pacific Commerce Bank, N.A. ("FPCB"), the covenants of which include notification obligations for material litigation.
E. The Defendant
Lumos Photonics, Inc. ("Lumos") is a corporation organized under the laws of the State of Delaware. Lumos is headquartered at 9400 McNeil Drive, Building 7, Austin, Texas 78758, with an additional office located at 4750 Great America Parkway, Suite 320, Santa Clara, California 95054, and a fabrication facility at 3200 NE Shute Road, Hillsboro, Oregon 97124. Lumos is publicly traded on the Nasdaq Stock Market under the ticker symbol "LMPH." Lumos designs and manufactures silicon photonics components and modules, placing it in direct competition with OWS in the data center interconnect market. Lumos's largest institutional shareholder is Ridgeline Asset Management LLC, which holds an approximate 9.2% equity stake.
III. Proposed Custodian List
A. Overview and Selection Criteria
The proposed custodian list reflects a careful evaluation of OWS personnel (and one former employee) whose files are most likely to contain documents responsive to the anticipated scope of discovery in this action. Custodians were identified based on the following criteria:
•  Named inventors: Individuals listed as inventors on one or more of the four patents-in-suit, whose files are expected to contain invention disclosures, lab notebooks, experimental data, and communications relating to the conception and reduction to practice of the patented inventions.
•  Patent prosecution involvement: Individuals who participated in or managed the prosecution of the four patents-in-suit before the United States Patent and Trademark Office, including interactions with patent examiners, prior art evaluations, and claim drafting and amendment decisions.
•  Commercial product knowledge: Individuals involved in the design, development, testing, and commercialization of OWS's products that embody the patented technologies, particularly the OWS-400ZR and OWS-800LR coherent optical transceiver chipsets.
•  Competitor awareness: Individuals who received, generated, or disseminated competitive intelligence regarding Lumos Photonics and its products, including the LumosBridge 800G Optical Engine and LumosEdge 400ZR+ Pluggable Transceiver.
•  Litigation decision-making: Individuals who participated in the decision to initiate this enforcement action, including those who authorized the March 15, 2022 cease-and-desist letter and the April 28, 2022 board resolution authorizing the filing of suit.
The litigation hold notice distributed on June 1, 2022, was directed to these same individuals, as well as to certain additional persons identified through initial factual investigation who were believed to possess potentially relevant materials. The custodian list below represents a refined set of those individuals, reflecting our assessment of who is most likely to hold unique, non-duplicative, responsive documents material to the issues in this case.
B. Primary Custodians (8 Individuals)
We recommend that the following eight individuals be designated as primary custodians and that full collections be taken from their corporate data sources within the specified date range.
1. Dr. Priya Ramanathan — Chief Executive Officer & Co-Founder, OWS
Dr. Ramanathan is the CEO and Co-Founder of Optiwave Semiconductor Corp. She holds a Ph.D. in Electrical Engineering with a specialization in photonics from Stanford University. Dr. Ramanathan is a named inventor on the '567 Patent and the '678 Patent.
Custodial Relevance: Dr. Ramanathan's files are expected to contain documents relating to the conception and reduction to practice of the inventions claimed in the '567 Patent and the '678 Patent, including early-stage invention disclosures, technical memoranda, and communications with co-inventors. As CEO, Dr. Ramanathan was directly involved in strategic decisions regarding patent prosecution priority, licensing strategy, and the enforcement of OWS's intellectual property rights. Her files are also expected to contain communications with or about Lumos Photonics, including competitive intelligence analyses, market assessments, and any direct communications between the two companies (including any pre-litigation licensing discussions). Additionally, Dr. Ramanathan participated in and chaired board meetings at which the decision to litigate was discussed and approved, and her communications with OWS's Board of Directors — including representatives of VPCP — regarding the litigation strategy are potentially responsive to damages and willfulness issues.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Personal files on OWS network file servers
•  Board of Directors meeting materials and communications
•  Invention disclosure records
•  Executive presentations and strategy documents
2. Dr. Kevin Fong — Chief Technology Officer & Co-Founder, OWS
Dr. Fong is the CTO and Co-Founder of Optiwave Semiconductor Corp. Prior to co-founding OWS, Dr. Fong served as a principal engineer at a major semiconductor foundry, where he gained extensive experience in silicon photonics process development. Dr. Fong is a named inventor on three of the four patents-in-suit: the '567 Patent, the '234 Patent, and the '890 Patent.
Custodial Relevance: Dr. Fong is central to the technical development underlying three of the four asserted patents. His files are expected to be among the richest sources of documents in this case. As CTO, Dr. Fong was directly involved in the design and specification of the OWS-400ZR and OWS-800LR products, which embody the patented technologies. He is likely the most knowledgeable individual at OWS regarding the technical distinctions between OWS's patented designs and the architecture of Lumos's accused products. Dr. Fong's engineering files, simulation data, design memoranda, and communications with co-inventors are expected to be critical to both the infringement and validity analyses. Additionally, Dr. Fong is relevant to prosecution history issues, as he may have participated in discussions with patent counsel regarding claim scope, prior art, and prosecution amendments. A deposition of Dr. Fong is currently scheduled for October 2022 during the claim construction discovery period, and document preparation for that deposition will draw heavily on materials collected from his custodial files.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Engineering design files (EDA project files, simulation results, layout files)
•  Lab notebooks (electronic format)
•  Internal technical memoranda and design review presentations
•  Patent prosecution correspondence (communications with Ted Marchetti and outside patent counsel)
•  Invention disclosure records
3. Dr. Amara Osei — Principal Engineer, OWS
Dr. Osei is a Principal Engineer at OWS, where she leads the photodetector and receiver design team. She is a named inventor on the '234 Patent and the '678 Patent.
Custodial Relevance: Dr. Osei's files are expected to contain documents relating to the design and development of germanium photodetector architectures, including the graded buffer layer technology claimed in the '234 Patent, as well as the WDM integration architecture claimed in the '678 Patent. Her files are particularly important for establishing the technical basis for OWS's proposed constructions of the claim terms "continuously varying germanium concentration" and "monolithically formed," both of which are disputed. Dr. Osei may also have generated or received comparative analyses of Lumos's photodetector and integration approaches. A deposition of Dr. Osei is currently scheduled for October 2022 during the claim construction discovery period.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Engineering design files (photodetector layout, simulation data, process characterization results)
•  Simulation data and modeling outputs
•  Invention disclosure records
•  Technical publications and conference presentations authored or co-authored by Dr. Osei
4. Theodore "Ted" Marchetti — Vice President of intellectual Property, OWS
Mr. Marchetti is the VP of intellectual Property at OWS. He is a registered patent attorney (USPTO Registration No. 58,304) and a former patent examiner at the United States Patent and Trademark Office (Art Unit 2828, which examines applications in the field of semiconductor devices and photonics).
Custodial Relevance: Mr. Marchetti managed the patent prosecution for all four patents-in-suit and was directly involved in claim drafting, prior art analysis, claim amendment strategy, and communications with the USPTO during prosecution. He prepared and sent the March 15, 2022 cease-and-desist letter to Lumos Photonics and coordinated with Calderwood & Harkness LLP and prior outside patent prosecution counsel regarding filing decisions and enforcement strategy. Mr. Marchetti maintains OWS's IP portfolio records, including the IP docketing system, prior art search records, and invention disclosure database. His files are also expected to contain licensing records relevant to damages analysis, including any prior licenses of the patents-in-suit or comparable OWS patents, as well as correspondence with Clearpath IP Valuation Services regarding the portfolio valuation.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Patent prosecution files (both electronic and any physical files)
•  IP docket system records
•  Correspondence with outside patent prosecution counsel
•  IP licensing and enforcement files
•  Prior art search records and analyses
•  Invention disclosure database records
•  Cease-and-desist correspondence and related files
Privilege Note: A significant portion of Mr. Marchetti's files is likely subject to the attorney-client privilege (communications with outside patent counsel, internal legal advice regarding patent scope and enforceability) and/or the work product doctrine (litigation preparation materials, pre-suit infringement analyses). These files will require especially careful privilege review. We recommend that a senior reviewer be assigned to Mr. Marchetti's document set during the review phase, and that any documents over which privilege is asserted be logged on the privilege log with sufficient detail to support the claim. We note that certain prosecution history materials — particularly communications with the USPTO — are not privileged and will be producible.
5. Sandra Ellison — General Counsel, OWS
Ms. Ellison serves as the General Counsel of Optiwave Semiconductor Corp. She holds a J.D. from the University of California, Berkeley School of Law, and oversees all legal affairs of the company, including intellectual property, corporate governance, compliance, and litigation management.
Custodial Relevance: Ms. Ellison provides legal oversight of this infringement action and serves as the primary liaison between OWS's in-house legal department and Calderwood & Harkness LLP. She is a recipient of legal advice regarding the patents-in-suit, the infringement analysis, the claim construction positions, and the litigation strategy. Ms. Ellison was a signatory on the Settlement Agreement (now the subject of enforcement proceedings) on behalf of OWS and was responsible for notifications to First Pacific Commerce Bank, N.A. under the covenants of OWS's $40 million revolving credit facility, which include material litigation notification obligations. Her files may also contain communications with OWS's Board of Directors and with VPCP regarding litigation budgeting and strategy.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Legal department files (contracts, engagement letters, outside counsel guidelines)
•  Board of Directors meeting minutes and materials
•  Engagement files and correspondence with Calderwood & Harkness LLP and any prior outside counsel
•  Notifications to and correspondence with First Pacific Commerce Bank, N.A.
Privilege Note: A heavy privilege overlay is expected for Ms. Ellison's document set. The vast majority of her communications with Calderwood & Harkness LLP will be protected by the attorney-client privilege and/or the work product doctrine. Internal communications in which Ms. Ellison provides legal advice to OWS management will similarly be privileged. As with Mr. Marchetti's files, careful privilege review will be required, and privilege determinations should be made by senior reviewers familiar with the applicable standards in the Northern District of California.
6. Rajesh Iyer — Circuit Designer, OWS
Mr. Iyer is a Circuit Designer in OWS's electronic design group. He is a named inventor on the '890 Patent.
Custodial Relevance: Mr. Iyer designed and developed the driver circuit architecture for MZM modulators that is claimed in the '890 Patent. His files are expected to contain detailed circuit design files, simulation data, and invention disclosures relating to the "pre-emphasis equalization stage electrically co-integrated with the modulator on a common substrate" limitation that is a key disputed claim term. Mr. Iyer is also a co-author of the Iyer & Patel article entitled "Co-Design of Modulator Drivers for Silicon Photonic Platforms" published in IEEE Transactions on Circuits and Systems in 2018, which Lumos has identified in its preliminary invalidity contentions as prior art against the '890 Patent under 35 U.S.C. § 103. Mr. Iyer's files relating to the preparation and publication of that article, as well as any internal analyses of how the article relates to the subsequently filed patent claims, are therefore potentially significant to both the validity and prosecution history issues in this case.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Circuit design files (schematic capture, layout, simulation results)
•  Simulation data and modeling outputs
•  Invention disclosure records
•  Published papers, drafts, and correspondence with co-authors and journal editors
7. Liwei Zhang — Design Engineer, OWS
Mr. Zhang is a Design Engineer at OWS specializing in integrated photonic transceiver design. He is a named inventor on the '678 Patent.
Custodial Relevance: Mr. Zhang was involved in the design and development of the multi-channel optical transceiver with integrated WDM on silicon that is claimed in the '678 Patent. His files are expected to contain engineering design files, simulation data, and communications relating to the monolithic versus heterogeneous integration approaches that are at the center of the construction dispute over the claim term "monolithically formed." Mr. Zhang's files may also shed light on the design choices OWS made in implementing the WDM integration for the OWS-400ZR and OWS-800LR products.
Data Sources:
•  OWS corporate email (Strathmore Data Systems / Ashbury Software)
•  Engineering design files (photonic component layout, waveguide routing, WDM filter design)
•  Invention disclosure records
•  Internal design review presentations and memoranda
8. Hideo Tanaka — Former OWS Engineer (2016–2019)
Mr. Tanaka is a former engineer at OWS who was employed by the company from 2016 to 2019. He is a named inventor on the '567 Patent. Notably, Mr. Tanaka is also an inventor of prior art — specifically, U.S. Patent No. 9,456,012, which was issued on September 6, 2016, and was co-invented by Mr. Tanaka before he joined OWS. The '9,456,012 patent was cited as a primary reference during prosecution of the '567 Patent, and the narrowing of the claims to add the "adiabatically coupled" limitation was undertaken during prosecution specifically to overcome the Tanaka prior art.
Custodial Relevance: Mr. Tanaka's files are critical to understanding the scope and prosecution history of the '567 Patent, particularly the prosecution history estoppel arguments raised by Lumos. Lumos contends that the claim amendments made to distinguish the Tanaka prior art estop OWS from asserting an interpretation of the '567 Patent claims broad enough to encompass the waveguide coupling architecture used in Lumos's accused products. Documents in Mr. Tanaka's files may illuminate the inventors' understanding of the distinction between the claimed "adiabatically coupled" structure and the structure disclosed in the Tanaka prior art patent. A deposition of Mr. Tanaka is scheduled for October 2022 during the claim construction discovery period, and his custodial documents will be essential for deposition preparation.
Data Sources:
•  OWS corporate email (archived, from the 2016–2019 employment period)
•  Engineering files (archived, from the 2016–2019 employment period)
•  Invention disclosure records
•  Any personal files retained by Mr. Tanaka (to the extent identifiable and recoverable)
Collection Note: Because Mr. Tanaka is a former employee who departed OWS in 2019, special steps are required to confirm the scope and integrity of preserved data. We must coordinate with OWS IT to locate and preserve Mr. Tanaka's archived email and file data. We should also confirm whether OWS retains copies of Mr. Tanaka's lab notebooks from the 2016–2019 period, which may exist in electronic or physical format. If any lab notebooks are in physical form only, arrangements should be made for scanning and inclusion in the review population. Additional considerations relating to Mr. Tanaka's former employee status are addressed in Section V.C below.
C. Potential Secondary Custodians
In addition to the eight primary custodians identified above, we have identified certain categories of OWS personnel who may hold responsive documents but who are not recommended as primary custodians at this time. We recommend deferring collection from these individuals pending completion of the primary custodian review and receipt of Lumos's specific document requests, at which point we can assess whether supplemental collections are warranted:
•  OWS Vice President of Sales or Business Development: This individual may hold documents containing competitive intelligence regarding Lumos's products, customer overlaps between OWS and Lumos, pricing comparisons for competing products, and market analysis data. Such documents could be relevant to damages issues (e.g., lost profits, price erosion, market share analysis) and to the willfulness inquiry (e.g., OWS's awareness of Lumos's infringing activities in the marketplace).
•  OWS finance and accounting personnel: Financial records relating to royalty rate analysis, revenue data for OWS's products practicing the patents-in-suit, profit margin data, research and development expenditures, and other financial information relevant to the Georgia-Pacific reasonable royalty analysis and any lost profits calculation may reside with OWS's finance and accounting team. These documents will likely be needed at the damages stage but may not be a priority during the initial claim construction and liability phases of discovery.
•  OWS IT administrator: The IT administrator is relevant primarily for system architecture and data mapping purposes — i.e., to assist in understanding OWS's data environment, identifying data repositories, and facilitating the forensic collection process. The IT administrator is not expected to hold substantive responsive documents on the merits of the case and accordingly is not recommended as a custodian for ESI collection purposes.
We will revisit the secondary custodian list following the completion of the primary custodian review and will make supplemental collection recommendations as warranted by the state of discovery.
D. Non-Custodial Data Sources
In addition to the custodial collections described above, the following non-custodial data sources should be collected or preserved for potential production:
•  Patent prosecution files maintained by Ted Marchetti and outside patent prosecution counsel: The complete prosecution histories for all four patents-in-suit, including file wrappers, office actions, responses, declarations, Information Disclosure Statements, and all other communications with the USPTO. To the extent that prior outside patent prosecution counsel (other than Calderwood & Harkness) handled prosecution of any of these patents, those files should be obtained.
•  OWS invention disclosure database: All invention disclosures associated with the four patents-in-suit, including the original disclosure forms, any supporting documentation, and records of the review and approval process.
•  OWS engineering design repository: EDA tool data, cadence and Ridgeline Data Systems project files, and associated documentation for the design and development of the technologies claimed in the patents-in-suit and the OWS-400ZR and OWS-800LR commercial products. Given the potentially large volume of design repository data, we recommend a targeted collection focusing on project directories identified by Dr. Fong and the engineering custodians as most relevant.
•  OWS product documentation repository: Datasheets, application notes, specification sheets, and marketing materials for the OWS-400ZR and OWS-800LR coherent optical transceiver chipsets, as well as any predecessor or successor products embodying the patented technologies.
•  Board of Directors meeting minutes and materials: Particularly the materials from the April 28, 2022 board meeting at which the Board authorized the filing of this litigation, and any other board meetings at which the Lumos infringement, patent enforcement strategy, or litigation budgeting were discussed.
•  IP licensing records: Any prior licenses of the patents-in-suit or comparable OWS patents, including term sheets, executed agreements, and negotiation correspondence. These records are directly relevant to the reasonable royalty damages analysis under the Georgia-Pacific framework.
•  Pinnacle Semiconductor Foundry process documentation: 45nm SOI process specifications, design rule manuals, and process characterization data to the extent relevant to manufacturing process comparisons between OWS's patented and commercial designs and Lumos's accused products. Access to Pinnacle's documentation may require coordination with Pinnacle under any applicable nondisclosure agreements and may implicate third-party confidentiality concerns.
IV. Proposed ESI Search Terms
A. Search Methodology
We propose the application of Boolean search term strings to the collected custodial data following standard processing steps, including de-duplication (both exact and near-duplicate identification), de-NISTing (removal of system files using the National Institute of Standards and Technology's National Software Reference Library hash sets), and filtering of non-responsive system-generated files (e.g., operating system files, application installation files, and other non-user-generated data).
Search terms will be applied to all text-searchable content within the processed data set, including:
•  Email body text
•  Email subject lines
•  Email attachment text (for text-based attachments)
•  Standalone document text (word processing documents, PDFs, spreadsheets, presentations)
•  OCR-extracted text for image-based documents (scanned documents, image-only PDFs)
The date range for the initial search term application will be January 1, 2015, through June 3, 2022 (the date on which the Complaint was filed in this action). The start date of January 1, 2015, has been selected to capture documents predating the earliest patent filing date (March 14, 2017, for the '567 Patent) by approximately two years, which should encompass the conception and early development phases for the patented inventions, as well as any prior art discussions or freedom-to-operate analyses that may be relevant to validity and prosecution history issues. Documents post-dating the Complaint filing will be collected and searched on a rolling basis as needed for ongoing discovery, including documents relating to the claim construction proceedings and any post-filing developments material to the litigation.
The search terms set forth below are designed to be over-inclusive at the collection stage. This approach is consistent with best practices for defensible ESI discovery and ensures that relevant documents are captured within the review population even if they use variant terminology or are not precisely anticipated by the search terms. Responsiveness and privilege determinations will be made during the substantive document review per the forthcoming Document Review Protocol Memorandum. We fully expect that the initial search term application will yield a substantial number of non-responsive documents (false positives), and we will employ iterative refinement and, if necessary, technology-assisted review to manage the review population efficiently.
B. Category 1: Patent-Specific Terms
The following terms are designed to capture documents that reference the patents-in-suit by number, abbreviation, or commonly used shorthand, as well as prior art patents identified as significant in the prosecution histories:
Patents-in-Suit:
•  "10,234,567" OR "10234567" OR "'567 patent" OR "567 patent"
•  "10,891,234" OR "10891234" OR "'234 patent" OR "234 patent"
•  "11,045,678" OR "11045678" OR "'678 patent" OR "678 patent"
•  "11,312,890" OR "11312890" OR "'890 patent" OR "890 patent"
Prior Art Patent Numbers:
•  "9,456,012" OR "9456012" — the Tanaka prior art patent, cited as a primary reference during prosecution of the '567 Patent and the basis for the claim narrowing that added the "adiabatically coupled" limitation
•  "EP 3,234,567" OR "EP3234567" OR "Nordlicht" — the Nordlicht Photonische GmbH European patent application (EP 3,234,567 A1), cited against the '234 Patent during prosecution
Patent Title Keywords:
•  "waveguide coupler" OR "tapered mode converter"
•  "germanium photodetector" OR "graded buffer layer"
•  "wavelength-division multiplexing" OR "WDM" (combined with "monolithic" OR "single die" OR "silicon" to reduce false positives from general WDM discussions unrelated to the patents)
•  "Mach-Zehnder modulator" OR "MZM driver" OR "modulator driver"
C. Category 2: Key Claim Term Search Terms
The following terms correspond to the disputed claim constructions across all four patents-in-suit. These terms are intended to capture documents in which OWS personnel discussed the patented technology using language that tracks or relates to the claim language at issue in the claim construction proceedings:
'567 Patent Claim Terms:
•  "adiabatic" OR "adiabatically coupled" OR "adiabatic coupl*"
'234 Patent Claim Terms:
•  "continuously varying" OR "continuously graded" OR "continuous grad" (AND "germanium" within 10-word proximity)
•  "step-graded" OR "step graded" OR "discrete composition" OR "composition step" — these terms are included to capture documents discussing alternative approaches or distinctions from the patented continuously graded technology, which may be relevant to both claim construction (defining the boundary of "continuously varying") and infringement analysis (assessing whether Lumos's approach falls within the claim scope)
'678 Patent Claim Terms:
•  "monolithically formed" OR "monolithic integration" OR "monolithic*"
•  "heterogeneous integration" OR "hybrid integration" OR "micro-transfer print" OR "flip-chip bond" — these terms are relevant to the construction dispute over whether "monolithically formed" excludes heterogeneous integration techniques; documents discussing these alternative integration approaches in the context of OWS's technology development and competitive analysis may bear on the proper construction of this term
'890 Patent Claim Terms:
•  "co-integrated" OR "co-integrat*" OR "common substrate" (AND "driver" OR "modulator" within 10-word proximity)
•  "pre-emphasis equalization" OR "pre-emphasis" (AND "modulator" OR "driver" within 10-word proximity)
•  "copper pillar" OR "micro-bump" — these terms relate to the physical interconnect structures alleged to be used in the accused LumosBridge product's modulator driver design and are relevant to the infringement analysis of the '890 Patent
D. Category 3: Accused Products and Competitor References
The following terms are designed to capture documents referencing Lumos Photonics, its products, and its key personnel:
•  "Lumos" OR "Lumos Photonics" OR "LPI" OR "LMPH"
•  "LumosBridge" OR "Lumos Bridge" OR "800G optical engine"
•  "LumosEdge" OR "Lumos Edge" OR "400ZR+" OR "400ZR plus"
•  "pluggable transceiver" (AND "Lumos" OR "competitor" within 15-word proximity)
•  "co-packaged optics" OR "CPO" (AND "Lumos" OR "competitor" OR "800G" within 15-word proximity)
•  "Harrelson" OR "Mei-Lin Chen" OR "Nikolai Petrov" — key Lumos personnel who may be referenced in competitive intelligence or technical comparison documents
•  "Ridgeline" OR "Ridgeline Asset Management" — Lumos's largest institutional shareholder (approximately 9.2% equity stake), which may be referenced in financial or market analysis documents
E. Category 4: OWS Product and Technology Terms
The following terms are designed to capture documents relating to OWS's own products and technologies that embody the patented inventions, which are relevant to both the infringement analysis (as evidence of how the patented technology is implemented) and the damages analysis (as evidence of OWS's commercial exploitation of the patents):
•  "OWS-400ZR" OR "OWS-800LR"
•  "coherent optical transceiver" OR "silicon photonics engine"
•  "Pinnacle" OR "Pinnacle Semiconductor" OR "45nm SOI" OR "45 nm SOI" — references to OWS's fabrication partner and process technology
•  "silicon photonics" OR "SiPh" OR "photonic integrated circuit" OR "PIC"
•  "data center interconnect" OR "DCI" OR "co-packaged optics"
F. Category 5: Patent Prosecution and IP Portfolio Terms
The following terms are designed to capture documents relating to the prosecution of the patents-in-suit, OWS's broader IP portfolio management, and IP valuation and licensing activities relevant to damages:
•  "patent prosecution" OR "office action" OR "examiner" OR "USPTO"
•  "claim amendment" OR "claim construction" OR "prosecution history"
•  "prior art" OR "anticipat" OR "obvious" OR "invalid*"
•  "patent valuation" OR "IP valuation" OR "Clearpath" — referencing the patent portfolio valuation conducted by Clearpath IP Valuation Services, which valued OWS's overall patent portfolio at $215 million and the four asserted patents at $42.8 million
•  "infringement" OR "infringe*"
•  "cease and desist" OR "cease-and-desist" OR "C&D letter"
•  "license" OR "licensing" OR "royalty" OR "cross-license"
G. Category 6: Litigation and Legal Terms
The following terms are designed to capture documents relating to the litigation itself, the engagement of counsel, settlement discussions, litigation funding evaluations, and financial reporting obligations triggered by the litigation:
•  "Calderwood & Harkness" OR "C&H" (in context of outside counsel references; we note that "C&H" may generate false positives and will need to be reviewed carefully during the relevance assessment)
•  "Brannick Howell" OR "BHS" — Lumos's defense counsel
•  "litigation" OR "lawsuit" OR "sue" OR "filing"
•  "settlement" OR "negotiate" OR "resolution"
•  "First Pacific Commerce" OR "FPCB" OR "revolving credit" — references to OWS's lender notification obligations under the covenants of its $40 million revolving credit facility
•  "Resolute" OR "litigation funding" OR "litigation finance" — references to the term sheet received from Resolute Litigation Finance LLC, which was ultimately declined by OWS; these documents are potentially responsive to damages and litigation strategy inquiries and will require careful privilege review
•  "Vantage Point" OR "VPCP" OR "Fairbanks" OR "Rebecca Torres" — references to OWS's majority shareholder, Vantage Point Capital Partners, and its representatives, whose communications with OWS management regarding the litigation may be responsive to discovery requests concerning litigation funding, damages expectations, and strategic decision-making
H. Category 7: Named Inventor-Specific Terms
The following terms are designed to be applied specifically within each inventor-custodian's files to capture invention-related documents:
•  "invention disclosure" OR "inventor*"
•  "conception" OR "reduction to practice"
•  "lab notebook" OR "experimental" OR "prototype"
•  "prior art search" OR "freedom to operate" OR "FTO"
•  Co-inventor name pairs in combination, to capture collaborative communications between the inventors on the patents-in-suit:
•  "Fong" AND "Ramanathan"
•  "Fong" AND "Osei"
•  "Ramanathan" AND "Zhang"
•  "Fong" AND "Iyer"
•  "Fong" AND "Tanaka"
•  "Osei" AND "Zhang"
•  "Ramanathan" AND "Osei"
•  "Iyer" AND "Fong" (alternative ordering, though search engines typically treat this equivalently)
These co-inventor name pair searches should be applied within the custodial files of the respective inventors to identify inter-inventor communications during the relevant time periods. To the extent that these searches yield an unmanageable volume of hits (given that these individuals may communicate frequently on many topics unrelated to the patents), we will consider adding proximity or contextual limiters.
I. Category 8: Prior Art and Publications
The following terms are designed to capture documents discussing specific prior art references and publications identified in the prosecution histories and Lumos's preliminary invalidity contentions:
•  "Chen & Liu" OR "segmented taper coupler" OR "Journal of Photonic Integration" — referencing the Chen & Liu 2016 article cited against the '567 Patent under 35 U.S.C. § 103 in combination with the Tanaka prior art patent
•  "Iyer & Patel" OR "Co-Design of Modulator Drivers" OR "IEEE Transactions on Circuits and Systems" — referencing the Iyer & Patel 2018 article cited against the '890 Patent under 35 U.S.C. § 103; of particular significance because OWS custodian Rajesh Iyer is a co-author of this article, and any internal OWS discussions about the relationship between the article's disclosures and the claims of the '890 Patent may be relevant to the validity defense and potentially to the prosecution history
•  "Nordlicht" OR "Nordlicht Photonische" — referencing European Patent Application EP 3,234,567 A1, assigned to Nordlicht Photonische GmbH, cited against the '234 Patent during prosecution
•  "Tanaka" AND ("prior art" OR "9,456,012" OR "patent") — to capture discussions of the Tanaka prior art patent and its relevance to the scope of the '567 Patent claims, including any internal analyses of the prosecution history estoppel arguments raised by Lumos
V. ESI Collection Protocol
A. Data Sources to be Collected
The following data sources should be collected for all eight primary custodians within the specified date range (January 1, 2015, through June 3, 2022, with rolling supplementation):
Corporate Email (Strathmore Data Systems / Ashbury Software): Full mailboxes for all eight primary custodians should be collected, including inbox, sent items, deleted items (to the extent recoverable), drafts, and any user-created folders. Email attachments should be collected together with their parent emails to preserve the parent-child relationship.
Network File Shares: Personal and project directories for each custodian on OWS's network file servers. The specific directory paths for each custodian should be identified in coordination with OWS IT, and all files within those directories should be collected.
Engineering Document Management System: Design files, simulation results, test data, and documentation stored in OWS's engineering document management system for the following project areas: OWS-400ZR coherent optical transceiver chipset, OWS-800LR coherent optical transceiver chipset, and any project directories associated with the technologies claimed in the four patents-in-suit. Given the potentially very large volume of EDA tool data (cadence and Ridgeline Data Systems project files), targeted collection should be performed in coordination with Dr. Fong and the engineering custodians to identify the most relevant project directories while preserving the ability to supplement the collection if needed.
Invention Disclosure System: All invention disclosures associated with the four patents-in-suit, as well as any invention disclosures for related technologies that may bear on the conception and development timeline.
IP Docketing System: Prosecution files for U.S. Patent Nos. 10,234,567; 10,891,234; 11,045,678; and 11,312,890, including complete file wrapper contents, docketing entries, and any associated work product or correspondence.
Board Meeting Portal: All materials from the April 28, 2022 board meeting at which the Board authorized the filing of this litigation, and any other board meetings at which the Lumos infringement, patent enforcement strategy, or related topics were discussed. This collection should include meeting agendas, presentations, resolutions, minutes, and any pre-meeting distribution materials.
Mobile Devices: If any of the eight primary custodians used personal or company-issued mobile devices (smartphones, tablets) for business communications related to the patents-in-suit or Lumos, text messages (SMS and Westmark Software) and messaging application data (including Meridian Solutions direct messages, Northgate Data Systems messages, and Meridian Services Inc. messages, if applicable) should be collected. Custodian interviews should be conducted to determine the scope of mobile device usage for business purposes.
B. Collection Method
Data collection should be performed by OWS's IT department under the direction and supervision of Calderwood & Harkness LLP. The collection method should adhere to the following standards:
•  Forensic imaging or forensic collection tools should be used for all data sources to ensure completeness and defensibility. Where full forensic imaging is not practicable (e.g., for cloud-based email or large shared file servers), targeted forensic collection using industry-standard tools (e.g., Ostrander Health IT, Severin Software, or equivalent) should be employed.
•  Collected data should be loaded into Calderwood & Harkness's document review platform (Relativity, hosted by [vendor to be confirmed]) for processing, de-duplication, de-NISTing, and search term application. Processing parameters (e.g., date filtering, file type filtering, OCR settings) should be documented and agreed upon with the review team.
•  Metadata must be preserved throughout the collection and processing chain. The integrity of key metadata fields — including date sent/received, to/from/cc/bcc, subject line, file creation date, last modified date, file path, and custodian identifier — must be maintained from collection through review through production.
•  Chain-of-custody documentation must be maintained for all collected data, documenting the date and time of collection, the identity of the collecting individual, the data source, the collection method, and the storage location. This documentation will support the defensibility of OWS's ESI production in the event of any challenge by Lumos.
C. Hideo Tanaka — Former Employee Special Considerations
Because Hideo Tanaka is a former employee who departed OWS in 2019, his custodial data requires special handling:
1.  Confirm preservation of archived data: We must confirm with Sandra Ellison and OWS IT that Mr. Tanaka's archived corporate email and file server data from his 2016–2019 employment period have been identified, located, and preserved pursuant to the June 1, 2022 litigation hold notice. If any of this data resides on backup tapes or other archival media, arrangements should be made to restore and collect it.
2.  Review separation agreement: We should review Mr. Tanaka's separation agreement and any related employment agreements to determine whether they contain provisions regarding (a) the return or retention of company documents and materials, (b) cooperation obligations with respect to intellectual property matters or litigation, or (c) IP assignment confirmations. Any cooperation clause may facilitate Mr. Tanaka's availability for deposition preparation and testimony.
3.  Personal copies of documents: If Mr. Tanaka retained any personal copies of documents relating to the '567 Patent invention — such as personal lab notebooks, personal email containing work-related discussions, or personal files containing design data — OWS's counsel may need to request their voluntary production or, depending on Mr. Tanaka's cooperation, take other appropriate steps. Given Mr. Tanaka's dual status as an inventor on both the asserted '567 Patent and the cited prior art patent (U.S. Patent No. 9,456,012), his personal files may be uniquely important.
4.  Lab notebooks: We should confirm whether OWS retains copies of Mr. Tanaka's lab notebooks from the 2016–2019 period. These notebooks may be in electronic format (if OWS used an electronic lab notebook system during that period) or in physical format (if paper lab notebooks were in use). If physical notebooks are located, they should be scanned and made available for review.
VI. Search Term Refinement and Quality Control
We propose an iterative refinement process to ensure that the proposed search terms achieve an appropriate balance between comprehensiveness (recall) and precision:
1.  Initial search term application: The search terms set forth in Section IV will be applied to the processed custodial data set, and the resulting hit counts per search term (and per custodian) will be tabulated.
2.  Sample review: For each search term or search term group producing a significant number of hits, a random sample of approximately 200 documents from the hit set will be reviewed by a member of the review team to assess the precision rate (i.e., the proportion of documents in the hit set that are actually responsive to one or more anticipated discovery topics) and to identify any systemic false-positive patterns.
3.  Precision and recall assessment: Based on the sample review results, we will assess whether any search terms are generating unacceptably high rates of false positives (low precision) or whether any significant categories of responsive documents appear to be missed by the current search terms (low recall). We will also compare the search term hit sets against the anticipated categories of Lumos's document requests to identify any gaps.
4.  Refinement: Search terms that are identified as overbroad will be refined using proximity connectors, additional Boolean limiters, or other techniques to improve precision without materially sacrificing recall. Search terms that appear to miss significant categories of responsive documents will be supplemented or expanded.
We have already identified several terms that are likely to generate high volumes of false positives if applied without limitation:
•  "WDM" standing alone: This acronym for wavelength-division multiplexing is pervasive in the silicon photonics literature and in OWS's engineering communications. Without a limiter, it is likely to yield a very large number of hits, many of which will relate to general WDM topics unrelated to the patented integration architecture. We recommend combining "WDM" with contextual terms such as "monolithic," "single die," or "silicon" as specified in Category 1.
•  "silicon" standing alone: Given that OWS is a silicon photonics company, virtually every technical document in the custodial data set is likely to contain the word "silicon." This term should not be used as a standalone search term but only in combination with more specific terms.
•  "driver" standing alone: This term is common in both technical and general business contexts and will likely generate excessive false positives. It should be used only in combination with "modulator," "MZM," "circuit," or other contextual terms as specified in Category 2.
Additionally, if the initial search term application yields a total review population exceeding 50,000 documents, we recommend discussing with Alan Ngo and the client the deployment of technology-assisted review (TAR), also known as predictive coding, as a cost-effective supplement to or replacement for linear human review. TAR has been widely accepted in the Northern District of California and can significantly reduce review costs while maintaining or improving review quality. The decision to implement TAR will depend on the actual volume of the review population, the projected review timeline, and the budget constraints discussed in Section IX below.
VII. Coordination with Lumos's discovery Requests
The search terms proposed in this memorandum have been designed to anticipate the likely scope of Lumos's document requests. Based on our experience in similar patent infringement cases and our understanding of Lumos's litigation positions as reflected in its preliminary claim construction contentions, we expect Lumos's requests to cover the following principal categories:
•  Documents relating to the conception, development, and reduction to practice of the inventions claimed in the four patents-in-suit
•  Patent prosecution files and related correspondence
•  Documents relating to the design, development, manufacture, and sale of OWS's commercial products that embody the patented technologies
•  Documents relating to Lumos and its accused products
•  Prior art references and analyses
•  Licensing and royalty records for the patents-in-suit and comparable patents
•  Financial records relevant to damages calculation
•  Communications with OWS's investors and lenders regarding the litigation
Lumos's first set of document requests — ultimately comprising 98 individual requests — is anticipated to be served in November 2022. The search terms above are designed to cast a sufficiently broad net to capture documents responsive to these anticipated request categories. Upon receipt of Lumos's actual requests, we will map the requests to our search term categories and assess whether any supplemental terms or custodians are needed.
In parallel, OWS's own first set of requests for production (112 requests) and first set of interrogatories (25 interrogatories) are being prepared for service on Lumos on November 21, 2022. The preparation of OWS's discovery requests is being handled by the broader litigation team and is not addressed in this memorandum.
ESI protocol negotiations with Brannick Howell & Stein LLP are ongoing. We have been in communication with Daniel Kowalski, Associate Team Lead at BHS, regarding the format, form of production (TIFF images with extracted text and metadata load files), Bates numbering conventions, de-duplication methodology, and other technical aspects of the parties' respective ESI productions. Any provisions agreed upon in the ESI protocol will be incorporated into our collection and search methodology as appropriate. We will circulate a draft ESI protocol stipulation for Alan Ngo's review once negotiations are sufficiently advanced.
VIII. Estimated Volume and Timeline
Based on our preliminary assessment of the custodial data environment — informed by discussions with OWS IT and initial data mapping — we estimate the following volumes and propose the following timeline:
These estimates are preliminary and will be refined once actual collections are processed. The wide range of the review population estimate (40,000–70,000 documents) reflects uncertainty regarding the volume of engineering design files and the precision of certain search terms that may require refinement as described in Section VI.
Proposed Timeline:
The accelerated timeline for the initial production is driven by the October 31, 2022 close of the claim-construction discovery period. We will prioritize for early review those documents most likely to be relevant to claim construction issues, including prosecution history materials, inventor communications regarding claim terminology, and technical documents bearing on the meaning of disputed claim terms. The balance of the document review will proceed on a rolling basis through January 2023, with productions made at regular intervals as review batches are completed.
We note that this timeline is aggressive, particularly given the compressed claim construction discovery schedule. If the actual review population is at the higher end of our est