Cisco Systems, Inc. et al. v. Ramot at Tel Aviv University Ltd.

I'll research this case thoroughly using web search before drafting the overview.

Let me dig deeper into the patents, IPRs, and current status.

Case Overview: Cisco Systems, Inc. et al. v. Ramot at Tel Aviv University Ltd., No. 1:21-cv-01365-GBW (D. Del.)

Parties. The plaintiffs/counter-defendants are Cisco Systems, Inc. and its wholly-owned subsidiary Acacia Communications, Inc. Cisco is a Delaware corporation and one of the world's largest networking and telecommunications equipment makers; Acacia (a Massachusetts-founded coherent-optics supplier) makes high-speed optical transceiver modules and became a Cisco subsidiary when Cisco closed its ~$4.5B acquisition on March 1, 2021. The defendant/counter-claimant is Ramot at Tel Aviv University Ltd., which the court described as "the Business Engagement Center of Tel Aviv University ('TAU')" — the university's technology-transfer arm, which secures and licenses IP developed by TAU faculty, students, and researchers and "acts as the University's liaison to industry." See D.I. 51 (Nov. 14, 2022 Mem. Op.), https://storage.courtlistener.com/recap/gov.uscourts.ded.76636/gov.uscourts.ded.76636.51.0.pdf. So the case pits a large operating company buying optics capability against a university tech-transfer entity monetizing academic research — not a classic PAE, but an academic/NPE-adjacent assertion posture.

Technology and patents. The dispute centers on Ramot's "Linearized Optical Digital-to-Analog Modulator" patent family, developed by inventors Yossef Ehrlichman, Ofer Amrani, and Shlomo Ruschin at TAU. The invention addresses the Mach-Zehnder modulator's inherent non-linear (cosine-shaped) optical response by inserting a "digital-to-digital converter" (DDC) that maps an N-bit digital input word to an M-bit actuation pattern driving M electrodes (often M≥N), so the output better approximates a linear response; the case materials also describe a "direct digital drive" approach connecting digital CMOS directly to photonic modulators. The patents at issue in this docket are U.S. 11,133,872 (the "'872 patent," issued Sept. 28, 2021) and the earlier family member U.S. 9,031,417 (the "'417 patent," issued May 12, 2015); the same family also includes the '465, '535, '866, and '998 patents that were litigated and/or reexamined in the parallel disputes (metadata identifies '872 and '417 as the patents at issue here). The accused instrumentalities are Cisco/Acacia high-speed coherent optical transceivers, pluggable modules (e.g., CIM8, CFP2, OSFP, QSFP-DD), DSP ASICs and silicon-photonics ICs (e.g., Acacia AC1200/AC400 products), and the Cisco line cards and routers that incorporate them — 100G/400G+ optical interconnect gear used in data centers and telecom networks (a parallel DJ complaint analysis described the products as "analog-driven" vs. "digitally-driven" and argued the DSP/DAC and gray-coding/thermometer-coding drive schemes fall outside the claims), https://ai-lab.exparte.com/case/dct/ded/1:22-cv-00674/doc/analysis/1.

Procedural posture and venue. This is a declaratory-judgment action for non-infringement brought under 28 U.S.C. §§ 2201–2202, filed in the District of Delaware on September 28, 2021 — the very day the '872 patent issued — originally assigned to Judge Leonard P. Stark and later to Judge Gregory B. Williams (case now captioned 21-1365-GBW). Delaware matters here because Cisco and Acacia are Delaware corporations and because both sides raced to control the forum: Ramot had sued Cisco in E.D. Tex. in 2014 (dismissed) and again in 2019 on the '535 and '465 patents, where Judge Gilstrap stayed the case just six weeks before trial after the PTO issued preliminary claim rejections in ex parte reexaminations; Ramot then sued Acacia alone in Delaware, Cisco and Acacia filed preemptive DJ actions there, and the court famously criticized their 12:01 a.m. filing on the day the '998 patent issued as an "abuse of the Declaratory Judgment Act." Ramot counterclaimed for infringement in this case; claim construction occurred in 2024, and a November 14, 2024 Memorandum Opinion held claims 45–47 and 49–54 of the '998 patent indefinite while upholding others (MLex, https://www.mlex.com/mlex/articles/[2260191](/patent/2260191)/). In October 2025 Judge Williams denied a partial summary-judgment motion of no on-sale bar, holding the pre-AIA on-sale bar applied because a product sold more than a year before the priority date embodied the claimed invention even if kept secret (VitalLaw/IP Law Daily, Oct. 24, 2025), and Ramot has since filed a Federal Circuit appeal (No. 26-1280, filed Dec. 23, 2025), consolidated with No. 26-1277.

Why it's notable. Three threads make this case worth tracking: (1) IPR linkage — Cisco petitioned for inter partes review of the '872 patent (IPR2022-00575 and -00576, filed Feb. 16, 2022; IPR2022-01283), the PTAB instituted in Oct. 2022, and on April 13, 2026 the Federal Circuit affirmed the Board's unpatentability findings via Rule 36 in Appeals Nos. 24-1726/1727/1728 (panel: Moore, Mayer, Lourie), extinguishing the '872 patent's enforcement value against Cisco — a good illustration of IPR-as-defense in parallel DJ litigation. (2) Forum strategy and the DJ Act — the case is a frequently cited example of defendants using anticipatory Delaware DJ filings to preempt Texas suits, and of how that conduct colors the PTAB stay calculus (the court partly stayed but kept fact discovery open; see Patents Post-Grant, https://www.patentspostgrant.com/2023/01/ptab-stay-calculus-considers-dj-history/). (3) Market/industry context — the patents cover optical DAC/modulator linearization for coherent 100G/400G+ optical interconnects, a core technology in data-center and telecom networking and in co-packaged optics; the '872 cancellation reduces FTO risk for Cisco and other coherent-optics players, while the continuing reexaminations of the '535, '465, and '866 patents (with PTAB appeal hearings held Nov. 4, 2025) show the family fight is not over.

Sourcing note: The party descriptions, product categories, and the 12:01 a.m./abuse-of-the-DJ-Act finding are well grounded in the court's Nov. 14, 2022 Memorandum Order (D.I. 51) and the Nov. 2022

I'll research this case thoroughly using web search.

Let me dig deeper into specific events.

I'll research the docket and firm sources for counsel of record representing Cisco and Acacia in this case.

Let me dig into the specific docket entries and pro hac vice appearances in this case.

Let me verify the specific counsel appearances on the 21-1365 docket and confirm firm affiliations.

Counsel of Record for Plaintiffs (Cisco Systems, Inc. & Acacia Communications, Inc.) — Cisco v. Ramot, No. 1:21-cv-01365-GBW (D. Del.)

Verification caveat up front: I was able to confirm the Delaware local-counsel team directly from the complaint and docket-entry credits, and I could confirm the pro hac vice roster from the closely related Delaware dockets (C.A. No. 21-295 and 23-cv-12), where the same plaintiff group moved for the same attorneys' admission. I could not pull the live 21-1365 PACER docket sheet in this session, so I have not independently confirmed the complete, current appearance list in 21-1365 itself, nor whether any withdrawals have occurred since the 2024 claim construction and the October 2025 summary-judgment ruling. Treat the entries below as well-sourced but requiring a live-docket confirmation for filing-grade accuracy.

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1. Local (Delaware) counsel — confirmed on the 21-1365 docket

• Both are among the most prolific D. Del. patent litigators; Morris Nichols is a fixture as Delaware counsel in District of Delaware IP cases. Blumenfeld is a long-serving member of the firm's IP group and a frequent Delaware counsel in ANDA and patent matters.
• Caveat: I have not verified current individual attorney profiles on the Morris Nichols site in this session; the "notable experience" characterization rests on the firm's well-documented D. Del. patent practice rather than on a specific cited bio.

2. Lead / trial counsel (pro hac vice, out-of-state) — Duane Morris LLP

Plaintiffs' substantive trial team appears to be the Duane Morris LLP patent litigation group, admitted pro hac vice alongside Morris Nichols:

Basis for this list:

• In Ramot at Tel Aviv University, Ltd. v. Acacia Communications, Inc., No. 1:21-cv-00295 (D. Del.), Judge Stark granted Acacia's motion for pro hac vice admission of "L. Norwood Jameson, Matthew C. Gaudet, Matthew S. Yungwirth, John R. Gibson, Sajid Saleem, Joseph A. Powers, Gilbert A. Greene and Evan J. Muller" (order entered 4/20/2021), with Blumenfeld's firm as local counsel. That is the companion Delaware action brought by the same patentee against the same plaintiff group.
• In Ramot at Tel Aviv University Ltd. v. Cisco Systems, Inc., No. 1:23-cv-00012 (D. Del.), CISCO moved for pro hac vice admission of "L. Norwood Jameson, Matthew C. Gaudet, Joseph A. Powers, Holly E. Engelmann, Sajid Saleem, and Daniel Mitchell" (D.I. 57, granted 1/20/2023), with Jennifer Ying noting her appearance for Cisco (D.I. 56).

Important accuracy note: I am inferring that this same Duane Morris team is the pro hac vice team in 21-1365 because (a) it is the same client group, (b) the same Delaware local counsel (Morris Nichols / Blumenfeld / Ying) appears across all three Delaware matters, and (c) the 2022–2025 substantive briefing in the 21-1365/22-674 family is consistent with that team. I have not seen the specific 21-1365 pro hac vice order in this session. If precision matters, the docket entries to pull are the motions for pro hac vice admission filed in 21-1365 in late 2021 / early 2022.

3. Roles I could NOT confirm

• In-house counsel. Cisco and Acacia are Delaware corporations; Cisco acquired Acacia on March 1, 2021 (D.I. 51 at 2–3), and Acacia is a wholly-owned Cisco subsidiary. I found no named in-house attorney appearing on the 21-1365 docket in the sources reviewed. Do not assume one.
• Sealed filings. I have no evidence of sealed appearances or of counsel appearing under seal in this matter; appearances in D. Del. patent cases are ordinarily public.

4. Adjacent counsel — do not confuse these with the 21-1365 plaintiff team

• PTAB (IPR2022-00575 / -00576, '872 patent): Petitioner Cisco was represented by Haynes & Boone LLP — Theodore Foster, David McCombs, Calmann Clements. That is a separate PTAB representation, not the district-court team. (Patent Owner Ramot was represented by Bunsow De Mory LLP, with Brenda Entzminger as lead counsel.)
• E.D. Tex. branch (No. 2:22-cv-00168-JRG; also the earlier 19-cv-225 action): Cisco appeared there through Desmarais LLP (Tamir Packin, Leslie Spencer, Deborah J. Mariottini, Jordan Owens, Michael R. Rhodes, Jonathan Lewis) with Gillam & Smith LLP as local counsel. Different forum, different team.
• Defendant Ramot's Delaware counsel has included Bunsow De Mory and, per a 2025 summary-judgment write-up, Ashby & Geddes; I did not verify the current defendant-side roster and it is outside your question.

5. Suggested next step to harden this

Pull the live 21-1365 docket and confirm: (i) the pro hac vice order granting the Duane Morris attorneys; (ii) whether any of them have withdrawn (cf. D.I. 58, Notice of Withdrawal of Counsel, in 23-cv-12); and (iii) the counsel block on the most recent substantive filings (the Sept. 17, 2024 claim construction opinion and the Oct. 2025 on-sale-bar summary-judgment ruling), plus the Federal Circuit appeal in Cisco Systems, Inc. v. Ramot at Tel Aviv University Ltd., No. 2024-1726, which will list appellate counsel separately.

Sources: D. Del. C.A. No. 21-1365 D.I. 1, 4, 6; C.A. No. 21-295 D.I. 8 (pro hac vice order, 4/20/2021); C.A. No. 23-cv-12 D.I. 56–57; D. Del. Memorandum Order in 21-1365 (IPR stay) and Memorandum Opinion, D.I. 51 (11/14/2022); PTAB IPR2022-00575/00576 pro hac vice decision (8/30/2022); E.D. Tex. No. 2:22-cv-00168-JRG Dkt. 52; ipde.com summary of the Oct. 2025 SJ ruling.

I'll research the docket and counsel for Ramot at Tel Aviv University Ltd. in this case.

Let me dig into the docket-specific counsel appearances and the recent filings.

Let me look at the actual docket entries for the Delaware case to confirm appearances and local counsel.

Counsel of record for the defendant — Ramot at Tel Aviv University Ltd.

Bottom line: Ramot (the defendant/counterclaim-plaintiff in 1:21-cv-01365-GBW) has been represented throughout this litigation by Bunsow De Mory LLP (Redwood City, CA), with Denise M. De Mory as lead/attorney-in-charge and Corey A. Johanningmeier as her principal co-counsel. For the current Federal Circuit appeals out of this case, Ramot has also retained appellate specialists MoloLamken LLP. I was not able to verify Ramot's Delaware local counsel of record from the sources I could retrieve — that gap is flagged below.

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Core litigation team — Bunsow De Mory LLP