1014-00005 · Optiwave Semiconductor Corp · Correspondence/External

letter-to-breitenfeld-vogt-b3-status.docx DOCUMENT IP / Technology

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PRIVILEGED & CONFIDENTIAL — ATTORNEY WORK PRODUCT

CALDERWOOD & HARKNESS LLP 555 California Street, 42nd Floor San Francisco, California 94104

Intellectual Property Group

Telephone: (415) 773-6000 Facsimile: (415) 773-6001 www.calderwoodharkness.com

November 30, 2023

Dr. Matthias Vogt Breitenfeld & Vogt Patentanwälte PartGmbB Leopoldstrasse 44 80802 Munich Germany

Re: European Patent Application No. EP 23 741 682.3 — Status Inquiry and Deadline Confirmation

Client: Optiwave Semiconductor Corp.

Our Reference: C&H Matter No. 1014-00005

Applicant: Optiwave Semiconductor Corp., 4710 Ridgeview Parkway, Suite 300, Santa Clara, CA 95054

Title of Invention: Multi-Channel Silicon-Photonic Mach-Zehnder Modulator with Segmented Traveling-Wave Electrode Architecture (Sub-Family B — including related electrode fabrication process claims)

Named Inventors: Dr. Rajan Menon; Dr. Lena Strickland; Dr. Feng-Yi Chen; Dr. Arjun Dasgupta

Priority Application: U.S. Provisional Application No. 63/297,841, filed January 10, 2022

Derived from: PCT/US2023/010584, filed January 9, 2023 (international phase completed; Chapter I International Search Report and Written Opinion issued July 14, 2023)

European Regional Phase Entry Date: July 5, 2023

Dear Dr. Vogt,

1. Purpose of Correspondence

Calderwood & Harkness LLP ("C&H") serves as outside patent counsel to Optiwave Semiconductor Corp. ("OWS" or the "Client") in connection with the above-referenced European patent application, EP 23 741 682.3 (hereinafter "B3"), and related matters within the OWS international patent portfolio. We appreciate the excellent and professional representation that Breitenfeld & Vogt Patentanwälte PartGmbB ("B&V") has provided as our European professional representatives for the OWS filings, and we write to you today in that capacity.

The purpose of this letter is to request a comprehensive status update regarding the Extended European Search Report ("EESR") that we understand the European Patent Office ("EPO") has recently issued for B3, and to confirm the applicable statutory deadline for filing a response to the EESR and the accompanying search opinion. In addition, we wish to address several related administrative and procedural matters concerning the OWS European docket, as described in further detail below.

For your reference, the working associate at C&H responsible for the day-to-day handling of international patent filings and office-action responses for the OWS docket is Peter Vassiliev, a registered patent attorney before the United States Patent and Trademark Office (USPTO Reg. No. 79,514). Mr. Vassiliev is the primary C&H contact for all matters relating to B3 and the other OWS European applications. The engagement is supervised by Catherine Bloom, Partner in the intellectual Property Group at C&H (USPTO Reg. No. 58,412), who remains the responsible partner for the OWS relationship. All substantive correspondence and strategic inquiries should be directed to Mr. Vassiliev in the first instance, with copies to Ms. Bloom as appropriate.

2. Acknowledgment of EESR Receipt

We have been informed, through our internal docketing system and through communication with the Client's in-house patent counsel, that the EPO issued the Extended European Search Report for EP 23 741 682.3 on or about November 17, 2023. This is consistent with the expected timeline given the July 2023 regional phase entry date and the prior completion of the international search during the PCT phase.

We respectfully request that B&V confirm receipt of the EESR from the EPO and advise us of the deemed notification date calculated in accordance with Rule 126(2) of the European Patent Convention ("EPC"). As you are aware, Rule 126(2) EPC provides that notifications sent by the EPO by postal services are deemed to have been delivered to the addressee on the tenth day following the date of posting, unless the letter has failed to reach the addressee or has reached the addressee at a later date. Accordingly, based on an issuance date of November 17, 2023, we calculate the deemed notification date to be approximately November 27, 2023. We would appreciate B&V's independent confirmation of this calculation, including any adjustments that may apply under the specific circumstances of this notification.

Furthermore, we request that B&V transmit to C&H a complete copy of the EESR as received from the EPO, including without limitation the following:

• The search report itself, identifying all cited prior art documents and their relevance categories (X, Y, A, D, P, E, or L);

• The accompanying search opinion (referred to in EPO practice as the "Communication under Rule 62 EPC" or the written opinion appended to the search report), setting forth the examiner's preliminary assessment of novelty, inventive step, industrial applicability, and any other substantive or formal objections;

• Complete copies of all prior art references cited in the search report, to the extent received from the EPO or available through B&V's files; and

• Any additional correspondence, forms, or notifications received from the EPO in connection with B3 that have not yet been forwarded to C&H.

Please transmit these materials to C&H at the street address set forth in the letterhead above and, in parallel, via electronic mail to Peter Vassiliev at pvassiliev@calderwoodharkness.com. If the volume of the cited references is substantial, transmission via a secure file-sharing platform would be acceptable; please contact Mr. Vassiliev to arrange access if necessary.

3. Response Deadline Confirmation

As you know, the procedural framework governing the applicant's response to the EESR in the context of a Euro-PCT application that has entered the European regional phase is set forth in Rule 70a EPC, read in conjunction with Rules 161 and 162 EPC and the relevant provisions of the Implementing Regulations. Specifically, Rule 70a(1) EPC provides that where the European Patent Office has drawn up a supplementary European search report, the applicant shall be invited to comment on the report and, where necessary, to amend the description, claims, and drawings within a period of six months from notification of the search report.

Based on the EESR issuance date of November 17, 2023, and applying the ten-day postal delivery presumption under Rule 126(2) EPC to yield a deemed notification date of approximately November 27, 2023, we calculate the six-month response deadline under Rule 70a(1) EPC as falling on or about May 27, 2024. However, we note that the interplay between Rule 70a and the provisions of Rules 161 and 162 EPC — particularly in circumstances where a Rule 161/162 response has already been filed — can introduce complexities in the deadline calculation. We are also mindful that the EPO's calculation of time limits under Rule 131 EPC (specifically the provision that a period expressed in months expires on the day of the last month which has the same number as the day on which the period commenced) and Rule 134 EPC (extension of time limits to the next business day where the deadline falls on a weekend or official holiday) may result in a slightly different date than our preliminary calculation.

We therefore request that B&V independently verify and confirm the precise response deadline, taking into account the following factors:

• The exact date of deemed notification under Rule 126(2) EPC as calculated by B&V based on the actual postal date reflected on the EPO's communication;

• Any applicable adjustments under Rule 131(4) EPC regarding the computation of periods expressed in months;

• Whether the calculated deadline falls on a non-business day within the meaning of Rule 134(1) EPC, and if so, the adjusted deadline; and

• Whether any other procedural considerations — including any extension provisions under the Rules of Procedure of the Boards of Appeal or other EPO administrative practice — may affect the deadline.

Please advise us of B&V's confirmed deadline calculation at your earliest convenience. It is critical that there be no ambiguity regarding this date, as the failure to file a timely response would have serious consequences for the prosecution of B3, potentially resulting in the application being deemed withdrawn under Article 94(3) EPC and Rule 71a EPC.

We also note that the response to the EESR will need to address any objections raised in the accompanying search opinion. Depending on the nature and severity of the examiner's objections, this may require substantive amendment of the claims, revision of the description to ensure consistency with any amended claims, and the preparation of detailed arguments regarding novelty, inventive step, and any other issues identified by the examiner. We will provide further instructions regarding the substance of the response once we have had the opportunity to review the EESR and search opinion and to consult with the Client's technical team.

4. Current Docket Status and Budget Constraints

We wish to advise you of certain administrative developments that may affect the timing and scope of prosecution activities on the OWS European patent applications in the near term. The Client has recently implemented a temporary budget-reduction program affecting discretionary intellectual property expenditures across its patent portfolio. This program has been adopted in response to broader corporate financial planning considerations and is not a reflection of the Client's commitment to its core IP assets, including the silicon-photonic modulator technology that is the subject of B3 and the related applications.

As a consequence of this budget-reduction program, the Client has directed C&H to implement a temporary hold on active prosecution activities — including the preparation of office-action responses, voluntary amendments, and related substantive work product — across the OWS patent docket, except where required to preserve statutory deadlines. This hold applies to the European applications as well, and accordingly, active prosecution work on B3 and the related European filings has been temporarily paused pending further instruction from the Client.

We wish to emphasize, however, that this hold does not extend to deadline monitoring, docketing, or any actions necessary to preserve the Client's rights. C&H continues to maintain and actively monitor all statutory and regulatory deadlines applicable to the OWS patent docket, including the response deadline for B3 discussed above. We will ensure that timely instructions are provided to B&V well in advance of the May 2024 response deadline (or such other date as B&V confirms), so that B&V has adequate time to prepare and file the response on behalf of the applicant.

In this regard, we respectfully request that B&V likewise continue to independently monitor the response deadline for B3 in your own docketing system and provide advance reminders to C&H at the following intervals:

• Six (6) months prior to the response deadline;

• Three (3) months prior to the response deadline; and

• One (1) month prior to the response deadline.

These reminders should be directed to Peter Vassiliev at the contact information provided below, with copies to the other C&H contacts identified in Section 7 of this letter. We believe that this layered approach to deadline monitoring — with independent tracking by both C&H and B&V — provides an appropriate safeguard against any inadvertent lapse and ensures that the Client's valuable patent rights are preserved throughout the prosecution process.

5. Related European Application C2

For completeness, and because we are writing to you regarding the OWS European docket generally, we wish to address the status of the related European patent application, EP 23 765 901.7, which we refer to internally as "C2." As you are aware, C2 pertains to Sub-Family C of the OWS silicon-photonic modulator patent portfolio, covering packaging and thermal management aspects of the technology. C2 entered the European regional phase on July 8, 2023, approximately three days after B3.

C&H prepared and filed the response to the EPO's Rule 161/162 communication for C2 through B&V on September 1, 2023. That response included certain voluntary amendments to the claims and description, as well as observations addressing the preliminary findings set forth in the Chapter I International Search Report and Written Opinion. To our knowledge, the EPO has not yet issued the Extended European Search Report for C2, and the application remains pending in the search phase.

Based on our understanding of current EPO processing times for supplementary European search reports in the semiconductor and photonics technology area (CPC class H04B, G02B, and related classifications), we estimate that the EESR for C2 may be issued in approximately mid-2025, though this timeline is of course subject to the EPO's internal workflow and priorities.

We request that B&V provide any update regarding the current procedural status of C2, including whether any communications have been received from the EPO since the filing of the Rule 161/162 response in September 2023, and B&V's own estimate of the expected timing for issuance of the EESR. If B&V has received any informal communications from the examining division or search division regarding C2, we would appreciate being informed of those as well.

6. Specific Requests and Action Items

To summarize the foregoing, we respectfully request that B&V take the following actions and provide the following information at your earliest convenience:

1. Confirm receipt of the EESR. Please confirm that B&V has received the Extended European Search Report for EP 23 741 682.3 (B3), dated November 17, 2023, from the European Patent Office.

2. Transmit the EESR and supporting documents. Please transmit to C&H a complete copy of the EESR, including the accompanying search opinion (written opinion under Rule 62 EPC), all cited prior art references, and any other related EPO correspondence, via both postal mail and electronic mail as described in Section 2 above.

3. Confirm the response deadline. Please independently verify and confirm the deadline for filing a response to the EESR under Rule 70a EPC. Our preliminary calculation yields a deadline of approximately May 27, 2024. Please advise if B&V's calculation differs in any respect, and provide the basis for any discrepancy.

4. Provide preliminary observations on the EESR. To the extent B&V has had the opportunity to review the EESR and search opinion, please provide any preliminary observations regarding the examiner's findings, the relevance and materiality of the cited prior art references, and the likely scope and complexity of the response that will be required. We understand that a detailed analysis will follow once C&H has had the opportunity to review the materials and consult with the Client's engineering team, but any initial impressions from B&V would be helpful for our planning purposes.

5. Confirm status of C2. Please confirm the current procedural status of EP 23 765 901.7 (C2), including whether any communications have been received from the EPO since September 2023, and provide B&V's estimate of the expected timing for issuance of the EESR for C2.

6. Provide updated fee estimate for B3 response. Please provide an updated fee estimate for B&V's preparation and filing of the response to the EESR for B3 (EP 23 741 682.3). For reference, the prior estimate provided by B&V for this phase of prosecution was in the range of approximately €3,500 to €5,000 for B&V's professional fees, depending on the complexity of the examiner's objections and the extent of claim amendments required. Please also confirm whether the EPO examination fee (currently approximately €1,775 for a standard examination request, or approximately €580 for certain designated examination fees, as applicable) has already been paid in connection with B3, or whether this fee remains outstanding and will need to be remitted in conjunction with the EESR response.

7. Continue deadline monitoring and provide advance reminders. Please continue to independently monitor all applicable deadlines for B3 and C2 in B&V's docketing system, and provide advance reminders to C&H at the intervals specified in Section 4 above (six months, three months, and one month prior to each deadline).

We would appreciate B&V's response to the foregoing requests within approximately ten (10) business days of receipt of this letter, or sooner if practicable. If any of the requested information requires additional time to compile, please advise us of the expected timeline so that we can plan accordingly.

7. Contact Information and Communication Preferences

For your reference, the primary C&H contacts for all matters relating to the OWS European patent applications are as follows:

Primary Contact:

Peter Vassiliev Working Associate, intellectual Property Group Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104

Email: pvassiliev@calderwoodharkness.com

Telephone: (415) 773-6128 Direct Facsimile: (415) 773-6129

Secondary Contact:

Christy Bauer Lead Associate, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 74,329 Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104

Email: cbauer@calderwoodharkness.com

Telephone: (415) 773-6244

Supervising Partner:

Catherine Bloom Partner, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 58,412 Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104

Email: cbloom@calderwoodharkness.com

Telephone: (415) 773-6050

We request that B&V direct all correspondence, communications, and inquiries regarding the OWS European applications — including B3 (EP 23 741 682.3) and C2 (EP 23 765 901.7) — to the above-named contacts and reference C&H Matter No. 1014-00005 in all such communications. Please ensure that copies of all EPO communications and B&V correspondence are provided to both Mr. Vassiliev and Ms. Bauer simultaneously.

8. Client and Billing Information

All invoices for B&V's professional services and any disbursements incurred in connection with EP 23 741 682.3 (B3) and EP 23 765 901.7 (C2) should continue to be directed to the attention of Peter Vassiliev at Calderwood & Harkness LLP at the address set forth above. C&H coordinates all foreign associate billing with the Client and will process B&V's invoices in the ordinary course through our established billing procedures.

We note that C&H will relay any changes to billing instructions, payment terms, or invoicing procedures as the Client's budget-reduction program evolves. Should any modifications to the current billing arrangement become necessary, we will notify B&V in writing with reasonable advance notice. In the interim, B&V should continue to invoice in accordance with the existing fee schedule and billing practices that have been in effect for the OWS engagement.

For the avoidance of doubt, the Client, Optiwave Semiconductor Corp., remains the party ultimately responsible for all EPO official fees, foreign associate professional charges, and any other costs or expenses incurred in connection with the prosecution of the OWS European patent applications. C&H acts as the coordinating counsel and billing intermediary, but does not assume independent financial liability for such charges except as expressly agreed in writing.

We appreciate B&V's continued diligence and attention to the OWS European patent filings. The silicon-photonic modulator technology embodied in B3 and the related applications represents a core component of OWS's intellectual property portfolio, and it is of considerable strategic importance to the Client that the European patent rights be preserved and prosecuted to grant. Close coordination between our firms will be essential as we approach the May 2024 response deadline for B3, and we look forward to working with you to prepare a thorough and effective response to the EESR.

We would be grateful for B&V's prompt response to this inquiry. Should you have any questions regarding the matters addressed in this letter, or should you require any additional information or authorization from C&H, please do not hesitate to contact Mr. Vassiliev directly at the telephone number or email address set forth above.

Thank you for your courtesy and cooperation.

Very truly yours,

CALDERWOOD & HARKNESS LLP

By: ________

Peter Vassiliev Working Associate, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 79,514

cc: (via email)

Catherine Bloom, Partner, Calderwood & Harkness LLP (Responsible Partner)

Christy Bauer, Lead Associate, Calderwood & Harkness LLP

Sandra Koh, IP Manager / In-House Patent Counsel, Optiwave Semiconductor Corp.

Lisa Cheng, Account Manager, Trident intellectual Property Services, LLC (for docketing coordination)

Enclosures: None. (Documents requested from B&V as set forth herein.)

PRIVILEGED & CONFIDENTIAL — ATTORNEY WORK PRODUCT
CALDERWOOD & HARKNESS LLP 555 California Street, 42nd Floor San Francisco, California 94104
Intellectual Property Group
Telephone: (415) 773-6000 Facsimile: (415) 773-6001 www.calderwoodharkness.com
November 30, 2023
Dr. Matthias Vogt Breitenfeld & Vogt Patentanwälte PartGmbB Leopoldstrasse 44 80802 Munich Germany
Re: European Patent Application No. EP 23 741 682.3 — Status Inquiry and Deadline Confirmation
Client: Optiwave Semiconductor Corp.
Our Reference: C&H Matter No. 1014-00005
Applicant: Optiwave Semiconductor Corp., 4710 Ridgeview Parkway, Suite 300, Santa Clara, CA 95054
Title of Invention: Multi-Channel Silicon-Photonic Mach-Zehnder Modulator with Segmented Traveling-Wave Electrode Architecture (Sub-Family B — including related electrode fabrication process claims)
Named Inventors: Dr. Rajan Menon; Dr. Lena Strickland; Dr. Feng-Yi Chen; Dr. Arjun Dasgupta
Priority Application: U.S. Provisional Application No. 63/297,841, filed January 10, 2022
Derived from: PCT/US2023/010584, filed January 9, 2023 (international phase completed; Chapter I International Search Report and Written Opinion issued July 14, 2023)
European Regional Phase Entry Date: July 5, 2023
Dear Dr. Vogt,
1. Purpose of Correspondence
Calderwood & Harkness LLP ("C&H") serves as outside patent counsel to Optiwave Semiconductor Corp. ("OWS" or the "Client") in connection with the above-referenced European patent application, EP 23 741 682.3 (hereinafter "B3"), and related matters within the OWS international patent portfolio. We appreciate the excellent and professional representation that Breitenfeld & Vogt Patentanwälte PartGmbB ("B&V") has provided as our European professional representatives for the OWS filings, and we write to you today in that capacity.
The purpose of this letter is to request a comprehensive status update regarding the Extended European Search Report ("EESR") that we understand the European Patent Office ("EPO") has recently issued for B3, and to confirm the applicable statutory deadline for filing a response to the EESR and the accompanying search opinion. In addition, we wish to address several related administrative and procedural matters concerning the OWS European docket, as described in further detail below.
For your reference, the working associate at C&H responsible for the day-to-day handling of international patent filings and office-action responses for the OWS docket is Peter Vassiliev, a registered patent attorney before the United States Patent and Trademark Office (USPTO Reg. No. 79,514). Mr. Vassiliev is the primary C&H contact for all matters relating to B3 and the other OWS European applications. The engagement is supervised by Catherine Bloom, Partner in the intellectual Property Group at C&H (USPTO Reg. No. 58,412), who remains the responsible partner for the OWS relationship. All substantive correspondence and strategic inquiries should be directed to Mr. Vassiliev in the first instance, with copies to Ms. Bloom as appropriate.
2. Acknowledgment of EESR Receipt
We have been informed, through our internal docketing system and through communication with the Client's in-house patent counsel, that the EPO issued the Extended European Search Report for EP 23 741 682.3 on or about November 17, 2023. This is consistent with the expected timeline given the July 2023 regional phase entry date and the prior completion of the international search during the PCT phase.
We respectfully request that B&V confirm receipt of the EESR from the EPO and advise us of the deemed notification date calculated in accordance with Rule 126(2) of the European Patent Convention ("EPC"). As you are aware, Rule 126(2) EPC provides that notifications sent by the EPO by postal services are deemed to have been delivered to the addressee on the tenth day following the date of posting, unless the letter has failed to reach the addressee or has reached the addressee at a later date. Accordingly, based on an issuance date of November 17, 2023, we calculate the deemed notification date to be approximately November 27, 2023. We would appreciate B&V's independent confirmation of this calculation, including any adjustments that may apply under the specific circumstances of this notification.
Furthermore, we request that B&V transmit to C&H a complete copy of the EESR as received from the EPO, including without limitation the following:
• The search report itself, identifying all cited prior art documents and their relevance categories (X, Y, A, D, P, E, or L);
• The accompanying search opinion (referred to in EPO practice as the "Communication under Rule 62 EPC" or the written opinion appended to the search report), setting forth the examiner's preliminary assessment of novelty, inventive step, industrial applicability, and any other substantive or formal objections;
• Complete copies of all prior art references cited in the search report, to the extent received from the EPO or available through B&V's files; and
• Any additional correspondence, forms, or notifications received from the EPO in connection with B3 that have not yet been forwarded to C&H.
Please transmit these materials to C&H at the street address set forth in the letterhead above and, in parallel, via electronic mail to Peter Vassiliev at pvassiliev@calderwoodharkness.com. If the volume of the cited references is substantial, transmission via a secure file-sharing platform would be acceptable; please contact Mr. Vassiliev to arrange access if necessary.
3. Response Deadline Confirmation
As you know, the procedural framework governing the applicant's response to the EESR in the context of a Euro-PCT application that has entered the European regional phase is set forth in Rule 70a EPC, read in conjunction with Rules 161 and 162 EPC and the relevant provisions of the Implementing Regulations. Specifically, Rule 70a(1) EPC provides that where the European Patent Office has drawn up a supplementary European search report, the applicant shall be invited to comment on the report and, where necessary, to amend the description, claims, and drawings within a period of six months from notification of the search report.
Based on the EESR issuance date of November 17, 2023, and applying the ten-day postal delivery presumption under Rule 126(2) EPC to yield a deemed notification date of approximately November 27, 2023, we calculate the six-month response deadline under Rule 70a(1) EPC as falling on or about May 27, 2024. However, we note that the interplay between Rule 70a and the provisions of Rules 161 and 162 EPC — particularly in circumstances where a Rule 161/162 response has already been filed — can introduce complexities in the deadline calculation. We are also mindful that the EPO's calculation of time limits under Rule 131 EPC (specifically the provision that a period expressed in months expires on the day of the last month which has the same number as the day on which the period commenced) and Rule 134 EPC (extension of time limits to the next business day where the deadline falls on a weekend or official holiday) may result in a slightly different date than our preliminary calculation.
We therefore request that B&V independently verify and confirm the precise response deadline, taking into account the following factors:
• The exact date of deemed notification under Rule 126(2) EPC as calculated by B&V based on the actual postal date reflected on the EPO's communication;
• Any applicable adjustments under Rule 131(4) EPC regarding the computation of periods expressed in months;
• Whether the calculated deadline falls on a non-business day within the meaning of Rule 134(1) EPC, and if so, the adjusted deadline; and
• Whether any other procedural considerations — including any extension provisions under the Rules of Procedure of the Boards of Appeal or other EPO administrative practice — may affect the deadline.
Please advise us of B&V's confirmed deadline calculation at your earliest convenience. It is critical that there be no ambiguity regarding this date, as the failure to file a timely response would have serious consequences for the prosecution of B3, potentially resulting in the application being deemed withdrawn under Article 94(3) EPC and Rule 71a EPC.
We also note that the response to the EESR will need to address any objections raised in the accompanying search opinion. Depending on the nature and severity of the examiner's objections, this may require substantive amendment of the claims, revision of the description to ensure consistency with any amended claims, and the preparation of detailed arguments regarding novelty, inventive step, and any other issues identified by the examiner. We will provide further instructions regarding the substance of the response once we have had the opportunity to review the EESR and search opinion and to consult with the Client's technical team.
4. Current Docket Status and Budget Constraints
We wish to advise you of certain administrative developments that may affect the timing and scope of prosecution activities on the OWS European patent applications in the near term. The Client has recently implemented a temporary budget-reduction program affecting discretionary intellectual property expenditures across its patent portfolio. This program has been adopted in response to broader corporate financial planning considerations and is not a reflection of the Client's commitment to its core IP assets, including the silicon-photonic modulator technology that is the subject of B3 and the related applications.
As a consequence of this budget-reduction program, the Client has directed C&H to implement a temporary hold on active prosecution activities — including the preparation of office-action responses, voluntary amendments, and related substantive work product — across the OWS patent docket, except where required to preserve statutory deadlines. This hold applies to the European applications as well, and accordingly, active prosecution work on B3 and the related European filings has been temporarily paused pending further instruction from the Client.
We wish to emphasize, however, that this hold does not extend to deadline monitoring, docketing, or any actions necessary to preserve the Client's rights. C&H continues to maintain and actively monitor all statutory and regulatory deadlines applicable to the OWS patent docket, including the response deadline for B3 discussed above. We will ensure that timely instructions are provided to B&V well in advance of the May 2024 response deadline (or such other date as B&V confirms), so that B&V has adequate time to prepare and file the response on behalf of the applicant.
In this regard, we respectfully request that B&V likewise continue to independently monitor the response deadline for B3 in your own docketing system and provide advance reminders to C&H at the following intervals:
• Six (6) months prior to the response deadline;
• Three (3) months prior to the response deadline; and
• One (1) month prior to the response deadline.
These reminders should be directed to Peter Vassiliev at the contact information provided below, with copies to the other C&H contacts identified in Section 7 of this letter. We believe that this layered approach to deadline monitoring — with independent tracking by both C&H and B&V — provides an appropriate safeguard against any inadvertent lapse and ensures that the Client's valuable patent rights are preserved throughout the prosecution process.
5. Related European Application C2
For completeness, and because we are writing to you regarding the OWS European docket generally, we wish to address the status of the related European patent application, EP 23 765 901.7, which we refer to internally as "C2." As you are aware, C2 pertains to Sub-Family C of the OWS silicon-photonic modulator patent portfolio, covering packaging and thermal management aspects of the technology. C2 entered the European regional phase on July 8, 2023, approximately three days after B3.
C&H prepared and filed the response to the EPO's Rule 161/162 communication for C2 through B&V on September 1, 2023. That response included certain voluntary amendments to the claims and description, as well as observations addressing the preliminary findings set forth in the Chapter I International Search Report and Written Opinion. To our knowledge, the EPO has not yet issued the Extended European Search Report for C2, and the application remains pending in the search phase.
Based on our understanding of current EPO processing times for supplementary European search reports in the semiconductor and photonics technology area (CPC class H04B, G02B, and related classifications), we estimate that the EESR for C2 may be issued in approximately mid-2025, though this timeline is of course subject to the EPO's internal workflow and priorities.
We request that B&V provide any update regarding the current procedural status of C2, including whether any communications have been received from the EPO since the filing of the Rule 161/162 response in September 2023, and B&V's own estimate of the expected timing for issuance of the EESR. If B&V has received any informal communications from the examining division or search division regarding C2, we would appreciate being informed of those as well.
6. Specific Requests and Action Items
To summarize the foregoing, we respectfully request that B&V take the following actions and provide the following information at your earliest convenience:
1. Confirm receipt of the EESR. Please confirm that B&V has received the Extended European Search Report for EP 23 741 682.3 (B3), dated November 17, 2023, from the European Patent Office.
2. Transmit the EESR and supporting documents. Please transmit to C&H a complete copy of the EESR, including the accompanying search opinion (written opinion under Rule 62 EPC), all cited prior art references, and any other related EPO correspondence, via both postal mail and electronic mail as described in Section 2 above.
3. Confirm the response deadline. Please independently verify and confirm the deadline for filing a response to the EESR under Rule 70a EPC. Our preliminary calculation yields a deadline of approximately May 27, 2024. Please advise if B&V's calculation differs in any respect, and provide the basis for any discrepancy.
4. Provide preliminary observations on the EESR. To the extent B&V has had the opportunity to review the EESR and search opinion, please provide any preliminary observations regarding the examiner's findings, the relevance and materiality of the cited prior art references, and the likely scope and complexity of the response that will be required. We understand that a detailed analysis will follow once C&H has had the opportunity to review the materials and consult with the Client's engineering team, but any initial impressions from B&V would be helpful for our planning purposes.
5. Confirm status of C2. Please confirm the current procedural status of EP 23 765 901.7 (C2), including whether any communications have been received from the EPO since September 2023, and provide B&V's estimate of the expected timing for issuance of the EESR for C2.
6. Provide updated fee estimate for B3 response. Please provide an updated fee estimate for B&V's preparation and filing of the response to the EESR for B3 (EP 23 741 682.3). For reference, the prior estimate provided by B&V for this phase of prosecution was in the range of approximately €3,500 to €5,000 for B&V's professional fees, depending on the complexity of the examiner's objections and the extent of claim amendments required. Please also confirm whether the EPO examination fee (currently approximately €1,775 for a standard examination request, or approximately €580 for certain designated examination fees, as applicable) has already been paid in connection with B3, or whether this fee remains outstanding and will need to be remitted in conjunction with the EESR response.
7. Continue deadline monitoring and provide advance reminders. Please continue to independently monitor all applicable deadlines for B3 and C2 in B&V's docketing system, and provide advance reminders to C&H at the intervals specified in Section 4 above (six months, three months, and one month prior to each deadline).
We would appreciate B&V's response to the foregoing requests within approximately ten (10) business days of receipt of this letter, or sooner if practicable. If any of the requested information requires additional time to compile, please advise us of the expected timeline so that we can plan accordingly.
7. Contact Information and Communication Preferences
For your reference, the primary C&H contacts for all matters relating to the OWS European patent applications are as follows:
Primary Contact:
Peter Vassiliev Working Associate, intellectual Property Group Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104
Email: pvassiliev@calderwoodharkness.com
Telephone: (415) 773-6128 Direct Facsimile: (415) 773-6129
Secondary Contact:
Christy Bauer Lead Associate, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 74,329 Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104
Email: cbauer@calderwoodharkness.com
Telephone: (415) 773-6244
Supervising Partner:
Catherine Bloom Partner, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 58,412 Calderwood & Harkness LLP 555 California Street, 42nd Floor San Francisco, CA 94104
Email: cbloom@calderwoodharkness.com
Telephone: (415) 773-6050
We request that B&V direct all correspondence, communications, and inquiries regarding the OWS European applications — including B3 (EP 23 741 682.3) and C2 (EP 23 765 901.7) — to the above-named contacts and reference C&H Matter No. 1014-00005 in all such communications. Please ensure that copies of all EPO communications and B&V correspondence are provided to both Mr. Vassiliev and Ms. Bauer simultaneously.
8. Client and Billing Information
All invoices for B&V's professional services and any disbursements incurred in connection with EP 23 741 682.3 (B3) and EP 23 765 901.7 (C2) should continue to be directed to the attention of Peter Vassiliev at Calderwood & Harkness LLP at the address set forth above. C&H coordinates all foreign associate billing with the Client and will process B&V's invoices in the ordinary course through our established billing procedures.
We note that C&H will relay any changes to billing instructions, payment terms, or invoicing procedures as the Client's budget-reduction program evolves. Should any modifications to the current billing arrangement become necessary, we will notify B&V in writing with reasonable advance notice. In the interim, B&V should continue to invoice in accordance with the existing fee schedule and billing practices that have been in effect for the OWS engagement.
For the avoidance of doubt, the Client, Optiwave Semiconductor Corp., remains the party ultimately responsible for all EPO official fees, foreign associate professional charges, and any other costs or expenses incurred in connection with the prosecution of the OWS European patent applications. C&H acts as the coordinating counsel and billing intermediary, but does not assume independent financial liability for such charges except as expressly agreed in writing.
We appreciate B&V's continued diligence and attention to the OWS European patent filings. The silicon-photonic modulator technology embodied in B3 and the related applications represents a core component of OWS's intellectual property portfolio, and it is of considerable strategic importance to the Client that the European patent rights be preserved and prosecuted to grant. Close coordination between our firms will be essential as we approach the May 2024 response deadline for B3, and we look forward to working with you to prepare a thorough and effective response to the EESR.
We would be grateful for B&V's prompt response to this inquiry. Should you have any questions regarding the matters addressed in this letter, or should you require any additional information or authorization from C&H, please do not hesitate to contact Mr. Vassiliev directly at the telephone number or email address set forth above.
Thank you for your courtesy and cooperation.
Very truly yours,
CALDERWOOD & HARKNESS LLP
By: ________
Peter Vassiliev Working Associate, intellectual Property Group Registered Patent Attorney, USPTO Reg. No. 79,514
cc: (via email)
Catherine Bloom, Partner, Calderwood & Harkness LLP (Responsible Partner)
Christy Bauer, Lead Associate, Calderwood & Harkness LLP
Sandra Koh, IP Manager / In-House Patent Counsel, Optiwave Semiconductor Corp.
Lisa Cheng, Account Manager, Trident intellectual Property Services, LLC (for docketing coordination)
Enclosures: None. (Documents requested from B&V as set forth herein.)

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