OPTIWAVE SEMICONDUCTOR CORP. 2775 Augustine Drive, Suite 400 San Jose, California 95054 Tel: (408) 555-7200
March 15, 2022
Via Sundial Data Systems Overnight Delivery and Electronic Mail
CONFIDENTIAL — PRIVILEGED COMMUNICATION
Richard Talbot, Esq. General Counsel Lumos Photonics, Inc. 9400 McNeil Drive, Building 7 Austin, TX 78758
Copy also sent to: Lumos Photonics, Inc. 4750 Great America Parkway, Suite 320 Santa Clara, CA 95054
Re: Infringement of U.S. Patent Nos. 10,234,567 and 10,891,234 by Lumos Photonics, Inc.
Dear Mr. Talbot:
1. Introduction and Purpose
I write on behalf of Optiwave Semiconductor Corp. ("OWS" or the "Company") in my capacity as Vice President of intellectual Property. I am a registered patent attorney admitted to practice before the United States Patent and Trademark Office (USPTO Registration No. 58,304). This letter has been prepared with the assistance of our outside litigation counsel at Calderwood & Harkness LLP, San Francisco, California.
The purpose of this letter is to notify Lumos Photonics, Inc. ("Lumos") that certain of its products infringe at least two of OWS's United States patents, as described in detail below, and to demand that Lumos immediately cease all infringing activities and enter into a licensing arrangement with OWS on commercially reasonable terms. OWS takes the protection of its intellectual property rights seriously and trusts that Lumos will give this matter the prompt and careful attention it warrants.
By way of background, OWS is a Delaware corporation headquartered in San Jose, California. The Company specializes in the design and commercialization of silicon photonics integrated circuits for data center interconnects, telecommunications, and related high-bandwidth optical networking applications. OWS was co-founded by Dr. Priya Ramanathan, who serves as Chief Executive Officer, and Dr. Kevin Fong, who serves as Chief Technology Officer. Both Dr. Ramanathan and Dr. Fong are recognized leaders in the silicon photonics field, having authored numerous peer-reviewed publications and having been named as inventors on dozens of issued U.S. patents.
OWS holds a substantial and growing intellectual property portfolio consisting of eighty-seven (87) issued United States utility patents and fourteen (14) pending patent applications. This portfolio is concentrated in several core technology areas that are central to OWS's business and competitive position, including waveguide coupling architectures, germanium-on-silicon photodetector designs, and modulator driver architectures. The portfolio represents well over a decade of sustained investment in research, development, and innovation.
Two of these patents — U.S. Patent No. 10,234,567 (the "'567 Patent") and U.S. Patent No. 10,891,234 (the "'234 Patent") — are the subject of this letter. As explained in detail below, OWS's technical and legal analysis indicates that Lumos's products infringe the claims of these patents.
2. Identification of the Asserted Patents
2.1 U.S. Patent No. 10,234,567 ("the '567 Patent")
The '567 Patent is titled "Integrated Waveguide Coupler with Tapered Mode Converter for Silicon Photonics Platforms." The application underlying the '567 Patent was filed on March 14, 2017, and the patent issued on March 19, 2019. The named inventors are Dr. Kevin Fong, Dr. Priya Ramanathan, and Hideo Tanaka, each of whom was employed by OWS at the time of the invention and assigned all rights, title, and interest in the patent to OWS.
The '567 Patent covers an innovative integrated optical coupler architecture comprising a tapered silicon waveguide that is adiabatically coupled to a silicon nitride waveguide layer. This architecture is critical for achieving high-performance fiber-to-chip coupling in silicon photonics platforms, enabling low insertion loss and broadband operation across multiple wavelength bands used in modern optical communication systems. The coupler design disclosed and claimed in the '567 Patent represented a significant advance over the prior art at the time of filing, and it addresses a longstanding challenge in the silicon photonics industry — namely, the efficient transfer of optical power between a single-mode optical fiber and a sub-micron silicon waveguide on a photonics chip.
Of particular relevance to this letter are independent Claim 1, which is directed to an integrated optical coupler comprising a tapered silicon waveguide having a tip width of less than 200 nanometers that is adiabatically coupled to a silicon nitride waveguide layer, as well as dependent Claims 4, 7, 12, and 15, which cover specific structural configurations, dimensional ranges, and performance parameters of the coupler. These claims define a broad yet well-supported scope of protection for OWS's coupler technology.
The '567 Patent was granted after thorough examination by the USPTO, including two substantive office actions in which the examiner carefully considered the prior art before allowing the claims. The patent has not been the subject of any post-grant proceedings, and its validity is presumed under 35 U.S.C. § 282. The '567 Patent represents foundational technology in the silicon photonics coupling space, and OWS has relied upon it as a cornerstone of its product offerings and licensing program since its issuance.
2.2 U.S. Patent No. 10,891,234 ("the '234 Patent")
The '234 Patent is titled "Germanium-on-Silicon Photodetector with Graded Buffer Layer for Enhanced Responsivity." The application underlying the '234 Patent was filed on September 8, 2017, and the patent issued on January 14, 2021. The named inventors are Dr. Kevin Fong and Dr. Amara Osei, both of whom were employed by OWS at the time of the invention and assigned all rights, title, and interest in the patent to OWS.
The '234 Patent covers a germanium-on-silicon photodetector architecture featuring a graded buffer layer having a continuously varying germanium concentration positioned between the silicon substrate and the germanium absorber layer. This graded buffer layer architecture significantly enhances the responsivity of the photodetector while simultaneously reducing dark current, thereby enabling higher-performance, lower-power high-speed optical receivers suitable for 100 Gbaud and beyond applications. The innovation disclosed in the '234 Patent addressed a persistent trade-off in the prior art between responsivity and dark current in germanium-on-silicon photodetector designs, offering a solution that achieves superior performance on both metrics.
Claims 1, 3, 5, 8, and 11 of the '234 Patent are of particular relevance to the infringement allegations set forth in this letter. These claims encompass both the structural features of the graded buffer photodetector and certain process-related aspects of its fabrication, providing comprehensive coverage of the patented technology.
The '234 Patent was allowed by the USPTO after an examiner interview conducted on July 22, 2020, during which the examiner was presented with a detailed explanation of the distinctions between the claimed invention and the cited prior art. The resulting allowance reflects the novelty and non-obviousness of the claimed invention. Like the '567 Patent, the '234 Patent has not been the subject of any post-grant challenge, and its validity is presumed under 35 U.S.C. § 282.
A copy of each of the '567 Patent and the '234 Patent is enclosed with this letter for your reference.
3. OWS's Products and Commercial Significance
OWS has invested substantial financial, engineering, and human resources over many years in developing and commercializing its silicon photonics technology. The Company's product portfolio includes the OWS-400ZR and OWS-800LR coherent optical transceiver chipsets, which are designed for data center interconnect ("DCI") and metro transport applications, as well as integrated silicon photonics engines for co-packaged optics — a rapidly growing segment of the optical networking market. These products directly embody the patented technologies at issue in this letter, among other proprietary innovations.
OWS's silicon photonics chips are fabricated by Pinnacle Semiconductor Foundry Co., Ltd. on a specialized 45nm silicon-on-insulator ("SOI") process. The development and qualification of this fabrication process required substantial investment in process development, design rule optimization, and yield improvement, reflecting OWS's deep commitment to translating its patented innovations into commercially successful products.
The commercial significance of OWS's patent portfolio, and of the asserted patents in particular, cannot be overstated. OWS generated approximately $187.4 million in revenue in its most recently completed fiscal year, a substantial portion of which is directly attributable to products incorporating the technologies claimed in the '567 and '234 Patents. Moreover, OWS's patent portfolio has been independently valued at approximately $215 million by Clearpath IP Valuation Services, Inc., a nationally recognized intellectual property valuation firm. The '567 and '234 Patents represent a significant portion of that valuation, reflecting their importance to OWS's business, to the broader silicon photonics industry, and to the competitive landscape for data center and telecom optical components.
The patented technologies are central to OWS's competitive position in the data center interconnect and telecommunications markets. Any unauthorized use of these technologies by a competitor such as Lumos directly undermines OWS's ability to recoup its significant research and development investments and erodes the competitive advantage that OWS has earned through years of innovation.
4. Identification of Infringing Products
4.1 LumosBridge™ 800G Optical Engine
OWS has become aware that Lumos Photonics, Inc. manufactures, uses, sells, offers for sale, and/or imports into the United States its LumosBridge™ 800G Optical Engine (the "LumosBridge 800G"), a co-packaged optics engine designed for hyperscale data center switches. The LumosBridge 800G was first shipped to customers in the first quarter of 2022, and Lumos has publicly promoted this product through its website, product datasheets, press releases, and presentations at industry conferences.
Based on OWS's detailed analysis of publicly available product literature, datasheets, white papers, technical presentations, and peer-reviewed publications authored by Lumos personnel — including, without limitation, publications and presentations by Dr. Mei-Lin Chen, Chief Technology Officer of Lumos, and Dr. Nikolai Petrov, Vice President of Engineering, Photonics Division — the LumosBridge 800G incorporates waveguide coupling structures and photodetector architectures that practice the claims of both the '567 Patent and the '234 Patent. Specifically, the LumosBridge 800G appears to utilize a tapered silicon waveguide adiabatically coupled to a silicon nitride waveguide layer for fiber-to-chip coupling, as well as germanium-on-silicon photodetectors incorporating a graded buffer layer with a continuously varying germanium concentration.
OWS's analysis is based on information presently available and is subject to confirmation through additional investigation, including, if necessary, reverse engineering, electron microscopy, and other analytical techniques.
4.2 LumosEdge™ 400ZR+ Pluggable Transceiver
Similarly, OWS has become aware that Lumos manufactures, uses, sells, offers for sale, and/or imports into the United States its LumosEdge™ 400ZR+ Pluggable Transceiver (the "LumosEdge 400ZR+"), a QSFP-DD form factor pluggable optical transceiver module designed for metro and data center interconnect applications. The LumosEdge 400ZR+ has been in production since the third quarter of 2021 and is actively marketed and sold by Lumos in the United States and internationally.
OWS's preliminary technical analysis indicates that the LumosEdge 400ZR+ incorporates the same or substantially similar waveguide coupling and germanium-on-silicon photodetector technologies as those found in the LumosBridge 800G. Accordingly, OWS has concluded that the LumosEdge 400ZR+ practices at least the asserted claims of both the '567 Patent and the '234 Patent. As with the LumosBridge 800G, OWS's analysis of the LumosEdge 400ZR+ is based on publicly available information and is subject to further investigation and confirmation.
5. Basis for Infringement Allegations
5.1 Infringement of the '567 Patent
OWS's technical analysis indicates that the waveguide coupler structures incorporated in both the LumosBridge 800G Optical Engine and the LumosEdge 400ZR+ Pluggable Transceiver include a tapered silicon waveguide coupled to a silicon nitride waveguide layer. These structures meet the structural limitations recited in the asserted claims of the '567 Patent. In particular, the coupler architecture in Lumos's products employs a tapered silicon waveguide with a tip geometry consistent with the claimed tip width of less than 200 nanometers, and the coupling is achieved through an adiabatic mode conversion process designed to achieve minimal optical power loss during the transfer of light between the fiber and the silicon waveguide — consistent with the "adiabatically coupled" limitation recited in Claim 1 and its dependents.
Based on the foregoing, OWS has determined that Lumos's manufacture, use, sale, offer for sale, and/or importation of the LumosBridge 800G and LumosEdge 400ZR+ constitutes infringement of at least Claims 1, 4, 7, 12, and 15 of the '567 Patent under 35 U.S.C. § 271(a).
5.2 Infringement of the '234 Patent
OWS's technical analysis further indicates that the germanium-on-silicon photodetectors employed in Lumos's accused products — both the LumosBridge 800G and the LumosEdge 400ZR+ — utilize a graded buffer layer positioned between the silicon substrate and the germanium absorber layer. Based on available technical literature and presentations by Lumos's engineering personnel, this graded buffer layer exhibits a continuously varying germanium concentration, which is the hallmark feature of the architecture claimed in the '234 Patent. The design described in Lumos's own published materials meets the claimed limitation of a "graded buffer layer having a continuously varying germanium concentration" as recited in the asserted claims.
Based on the foregoing, OWS has determined that Lumos's manufacture, use, sale, offer for sale, and/or importation of the LumosBridge 800G and LumosEdge 400ZR+ constitutes infringement of at least Claims 1, 3, 5, 8, and 11 of the '234 Patent under 35 U.S.C. § 271(a).
5.3 Additional Patent Rights
In addition to the '567 and '234 Patents specifically addressed in this letter, OWS's patent portfolio includes additional issued patents and pending patent applications that may be relevant to Lumos's product line, including products beyond those specifically identified herein. By way of example, OWS holds U.S. Patent No. 11,045,678 (the "'678 Patent"), titled "Multi-Channel Optical Modulator Driver with Adaptive Equalization," which issued on June 29, 2021, and OWS has a patent application pending since November 15, 2018, directed to additional silicon photonics innovations that may be implicated by Lumos's product offerings.
OWS has not completed its analysis of all potentially relevant patents and applications, and this letter should not be construed as identifying the full scope of OWS's intellectual property rights that may be at issue. OWS expressly reserves all rights with respect to its full patent portfolio, including the right to assert additional patents and additional claims against Lumos and its products at any time.
6. Demand
In light of the foregoing, OWS hereby demands that Lumos Photonics, Inc. immediately take the following actions:
1. Cease and Desist. Lumos shall immediately cease and desist from the manufacture, use, sale, offer for sale, and importation into the United States of the LumosBridge™ 800G Optical Engine, the LumosEdge™ 400ZR+ Pluggable Transceiver, and any other products that infringe OWS's patents, including but not limited to the '567 Patent and the '234 Patent.
2. Written Confirmation. Lumos shall provide a written confirmation to OWS, within thirty (30) calendar days of receipt of this letter, that all infringing activities identified herein have ceased and that Lumos has taken affirmative steps to ensure that no further infringement will occur.
3. License Negotiations. Lumos shall enter into good-faith negotiations with OWS for a license agreement under OWS's relevant patents on commercially reasonable terms. OWS is prepared to engage promptly in such discussions and to work constructively toward a mutually acceptable resolution.
4. Accounting of Revenues. Lumos shall provide OWS with a complete and accurate accounting of all revenues derived from the sale, lease, or other disposition of the LumosBridge 800G, the LumosEdge 400ZR+, and any other infringing products, from the date of first sale through the date of Lumos's response to this letter. Such accounting shall include unit volumes, average selling prices, and total revenue figures, broken down by product and by quarter.
OWS wishes to emphasize that it is prepared to discuss a licensing arrangement that would permit Lumos to continue using the patented technologies under appropriate commercial terms. OWS's preference, as stated further below, is to resolve this matter amicably and without resort to litigation. However, OWS will not tolerate the continued unauthorized use of its patented technologies.
7. Notice and Willfulness
This letter constitutes formal notice to Lumos Photonics, Inc. of OWS's patent rights and of Lumos's infringement thereof. OWS hereby puts Lumos on actual, written notice that its continued manufacture, use, sale, offer for sale, and/or importation of the accused products after receipt of this letter may be deemed willful infringement within the meaning of 35 U.S.C. § 284. Under the Patent Act, willful infringement may subject an infringer to enhanced damages of up to three times the amount of actual damages found by the court or jury, as well as an award of attorneys' fees under 35 U.S.C. § 285 in exceptional cases.
OWS strongly urges Lumos to obtain a competent written opinion of counsel from a qualified patent attorney regarding the matters set forth in this letter, including the scope and validity of the asserted patents and the question of whether Lumos's products infringe the claims thereof. The failure to obtain such an opinion, or to take appropriate remedial action in response to this notice, may be relevant to a court's determination of willfulness and to the availability of enhanced damages.
OWS further notes that Lumos Photonics, Inc. is a publicly traded company listed on the Nasdaq Stock Market under the ticker symbol "LMPH." Lumos's continued infringement of OWS's patent rights, and the potential exposure to significant damages liability that infringement entails, may constitute a material risk that Lumos is obligated to disclose to its shareholders and to the investing public under applicable securities laws and regulations. OWS leaves it to Lumos and its advisors to assess Lumos's disclosure obligations in this regard.
8. Reservation of Rights
Nothing in this letter shall be construed as a waiver of any of OWS's rights or remedies, whether at law or in equity, all of which are expressly reserved in their entirety. Without limiting the generality of the foregoing, OWS specifically reserves the right to seek injunctive relief (including both preliminary and permanent injunctions), compensatory damages (including lost profits and/or reasonable royalties), enhanced damages for willful infringement, pre-judgment and post-judgment interest, attorneys' fees, costs, and any other remedies available under applicable law, including but not limited to the filing of a civil action for patent infringement in an appropriate United States District Court and/or the filing of a complaint with the United States International Trade Commission under Section 337 of the Tariff Act of 1930.
This letter is not intended to be, and shall not be construed as, a complete or exhaustive statement of OWS's claims, rights, or remedies against Lumos Photonics, Inc. OWS's technical and legal analysis of Lumos's products is ongoing, and OWS expressly reserves the right to identify additional infringing products, additional infringed patents, and additional bases for liability as its investigation continues. The omission of any claim, product, patent, or theory of liability from this letter shall not constitute a waiver or abandonment thereof.
9. Request for Response and Contact Information
OWS requests that Lumos Photonics, Inc. respond to this letter in writing within thirty (30) calendar days of receipt. Lumos's response should address each of the demands set forth in Section 6 above and should identify the individual or individuals at Lumos who will serve as the point of contact for further discussions regarding this matter.
All correspondence should be directed to:
Theodore "Ted" Marchetti Vice President, intellectual Property Optiwave Semiconductor Corp. 2775 Augustine Drive, Suite 400 San Jose, CA 95054
Email: tmarchetti@optiwavesemi.com
Tel: (408) 555-7244
with a mandatory copy to OWS's outside counsel:
Alan Ngo, Esq. Calderwood & Harkness LLP One Embarcadero Center, 34th Floor San Francisco, CA 94111
Email: ango@calderwoodharkness.com
Tel: (415) 555-3100
As stated above, OWS's strong preference is to resolve this matter through a licensing arrangement that is fair and reasonable to both parties, without the necessity of protracted and expensive litigation. OWS is prepared to engage in constructive, good-faith discussions toward that end at the earliest opportunity. However, please be advised that if Lumos fails to respond to this letter within the time specified, or if Lumos's response is unsatisfactory, OWS is fully prepared to protect its intellectual property rights through all available legal means, including the commencement of litigation in the appropriate forum.
We look forward to hearing from you.
Very truly yours,
OPTIWAVE SEMICONDUCTOR CORP.
By: ________
Theodore "Ted" Marchetti Vice President, intellectual Property Registered Patent Attorney, USPTO Reg. No. 58,304
cc: Sandra Ellison, General Counsel, Optiwave Semiconductor Corp.
cc: Alan Ngo, Esq., Calderwood & Harkness LLP
cc: Marcus Delgado, Esq., Calderwood & Harkness LLP
Enclosures:
1. Copy of U.S. Patent No. 10,234,567 — "Integrated Waveguide Coupler with Tapered Mode Converter for Silicon Photonics Platforms"
2. Copy of U.S. Patent No. 10,891,234 — "Germanium-on-Silicon Photodetector with Graded Buffer Layer for Enhanced Responsivity"