Omar,
Wanted to send a consolidated status update on all Markman hearing prep workstreams before we get into the final push. Hearing is five days out — Monday, January 30, before Judge Torvelis in *Optiwave Semiconductor Corp. v. Lumos Photonics, Inc.*, Case No. 5:22-cv-03417-EJD (N.D. Cal.). We're in good shape overall, but there are a few items that need final sign-off from you and Alan before the weekend. Details below.
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**1. Briefing Status — Complete**
Our Reply Claim Construction Brief (15 pages) was filed January 9 without issue. Lumos's Sur-Reply was filed January 19 by leave of Court (also 15 pages). I've reviewed it in full.
Summary of what Brannick Howell & Stein is doing: Victoria Ashworth's team doubled down on prosecution history estoppel on two fronts — (1) the '567 Patent, arguing that OWS's addition of "adiabatically coupled" during prosecution to overcome the Tanaka prior art (U.S. Patent No. 9,456,012) narrows the claim scope, and (2) the '678 Patent, arguing that the addition of "monolithically formed" to overcome hybrid integration references constitutes a surrender of equivalents. No real surprises there.
What *is* new: they attached a declaration from Dr. Raymond Ng (their technical consultant) on the meaning of "co-integrated" in the context of the '890 Patent. I'll pull the key paragraphs for the hearing binder and our rebuttal prep notes.
One thing worth flagging for oral argument prep: the Sur-Reply's estoppel argument on the '567 Patent cites applicant remarks from prosecution where OWS distinguished Tanaka by specifically emphasizing *continuous taper geometry*. Alan should be ready to address that head-on if the Court raises it. I'd recommend both of you take a look at the Dr. Ng declaration as well — I'll have the relevant excerpts pulled and organized by tomorrow afternoon.
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**2. Demonstrative Slides — Near Final**
The Northgate Services Inc. deck is substantially complete at approximately 48 slides, organized by patent across all 11 disputed claim terms. Here's where we are on the key sections:
- **'567 Patent — "adiabatically coupled":** Annotated patent figures showing the tapered silicon waveguide (tip width < 200 nm) adiabatically coupled to the silicon nitride waveguide layer. Side-by-side comparison of OWS's proposed construction ("coupled such that optical mode transitions occur without significant power loss") versus Lumos's proposed construction ("coupled through a gradual, continuous taper that prevents excitation of higher-order modes throughout the entire transition region"). Also includes a diagram of Lumos's LumosBridge segmented taper design showing how it practices the claims under our construction.
- **'234 Patent — "graded buffer layer having a continuously varying germanium concentration":** Diagram comparing continuously graded vs. step-graded SiGe buffers. Notation that Lumos uses four discrete composition steps (Ge fractions of 0.25, 0.50, 0.75, 1.0). Specification excerpts showing embodiments describing both "continuously graded" and "step-graded" buffer layers.
- **'678 Patent — "integrated wavelength-division multiplexing element monolithically formed on a single silicon die":** Visual comparing monolithic integration vs. heterogeneous integration approaches (micro-transfer-printing, flip-chip bonding). Notes that Lumos's 800G platform uses micro-transfer-printed III-V gain elements bonded to the silicon PIC.
- **'890 Patent — "pre-emphasis equalization stage electrically co-integrated with the modulator on a common substrate":** Diagram of Lumos's architecture showing separate CMOS driver die flip-chip bonded via copper pillar micro-bumps to the silicon photonic modulator die.
I've also included prosecution history timeline slides for the '567 and '678 Patents showing when claim amendments were made and what was surrendered — these should be useful for rebutting the estoppel arguments.
**Omar — I need your review and comments on slides 12–18** (the '567 Patent "adiabatically coupled" section) **by COB tomorrow, Thursday, January 26.** These are the most critical slides given how aggressively BHS is pushing on that term. I'm attaching the current deck to this email.
**Alan — I'll need your final sign-off on the full deck by EOD Friday, January 27.** I plan to have a final print-ready version locked down by end of day Friday.
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**3. Dr. Whitfield's Technical Tutorial Presentation**
Dr. Harold Whitfield (Whitfield Technical Consulting Group, Inc., Palo Alto) has finalized his technical tutorial — approximately 35 slides covering silicon photonics fundamentals, waveguide coupling physics, germanium photodetector architectures, monolithic vs. heterogeneous integration, and MZM driver co-integration. I'm attaching his deck as well.
I did a dry run with him on Monday at his office on Lytton Avenue. He's polished and very comfortable with the material. Estimated presentation time came in at 45–50 minutes, which should fit well within the Court's allotted tutorial time.
One item for discussion: Dr. Whitfield wants to add a brief section on adiabatic mode theory with some mathematical formalism — coupled-mode equations, that sort of thing. I recommended keeping it high-level and visual for Judge Torvelis, but I'd like Omar and Alan to weigh in. My instinct is to keep it conceptual only and save the math for any follow-up questions from the bench, but I defer to you both on this.
For awareness: Lumos's technical tutorial witness will be Dr. Raymond Ng (BHS's of counsel/technical consultant, formerly at University of Colorado Boulder). We should expect him to hammer the segmented vs. continuous taper distinction, so Alan should be ready to redirect on that during argument.
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**4. Dr. Whitfield's Declaration**
Quick reminder — Dr. Whitfield's Declaration in Support of OWS's Claim Construction was filed with our Opening Brief in December 2022. I don't think we need a supplemental declaration to respond to new points in the Sur-Reply, but I'm flagging it in case Alan feels differently. Happy to discuss.
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**5. Hearing Logistics**
- **When:** Monday, January 30, 2023, 9:00 AM - **Where:** Courtroom 4, 5th Floor, Robert F. Peckham Federal Building, San Jose - **Time allotted:** 6.5 hours total (confirmed with chambers) - **Arguing:** Alan Ngo for OWS; Victoria Ashworth for Lumos - **Dr. Whitfield** should arrive by 8:15 AM for setup. I'll coordinate his travel from Palo Alto.
**Prep session:** I've reserved a conference room at the Northpoint Holdings for Sunday afternoon, January 29, for a final moot/prep session with Alan, Dr. Whitfield, and the two of us. **Omar — can you confirm your availability for 2:00 PM?**
**Hearing binders:** I'm preparing three hard-copy binders — one for Alan at counsel table, one for Dr. Whitfield, and one backup. Each will include:
- Joint Claim Construction Statement (filed October 14, 2022) - OWS's Opening Claim Construction Brief - OWS's Reply Claim Construction Brief - Lumos's Responsive Brief and Sur-Reply - Dr. Whitfield's Declaration - Proposed claim constructions chart - Key prosecution history excerpts - Demonstrative slides (printed)
I've also prepared a laminated quick-reference card with all 11 disputed terms and each party's proposed constructions side-by-side for counsel table. Should be very handy for real-time reference during argument.
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**6. Action Items**
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I'll be in the office all day Thursday and Friday to finalize everything. Happy to set up a quick team call Thursday morning if that would be helpful — just let me know.
Thanks, Christy
--- Christy Bauer Associate Calderwood Harkness LLP cbauer@calderwoodharkness.com