Item 1.01 Entry into a Material Definitive Agreement. On September 1, 2025, Prime World International Holdings Ltd. (“ Prime World”), a wholly owned subsidiary of Applied Optoelectronics, Inc., entered into a Premises Lease Agreement (the “ Lease Agreement”) with International Games System Co., Ltd. (the “ Lessor”), under which Prime World will lease a parcel of land with a total area of approximately 65,580 square feet, designated as Land No. 560-3, located in the Wugong Section of Wugu District, New Taipei City. The lease also includes a building on the parcel, totaling approximately 346,212 square feet, situated at No. 49, Wugong 6th Rd., Wugu Dist., New Taipei City (collectively, the “ Leased Property”). The leasehold excludes approximately 54,086 square feet of the Leased Property that, as specified in the Lease Agreement, had previously been leased by the Lessor to an existing tenant. The lease term is for fifteen (15) years, commencing on November 1, 2025, and ending on October 31, 2040. A two-month renovation period from September 1 to October 31, 2025, will precede the lease term, during which no rent will be charged by the Lessor. During the lease term, the monthly rent will increase by three percent (3%) every five years. The monthly rent schedule, starting from November 1, 2025, through October 31, 2040, is as follows: Period Monthly Rent ────────────────────────────────────────────────────────── November 1, 2025 – October 31, 2030 NTD 6,800,000 November 1, 2030 – October 31, 2035 NTD 7,004,000 November 1, 2035 – October 31, 2040 NTD 7,214,120 Under the terms of the Lease Agreement, Prime World has the right, at its own expense, to modify the building within the Leased Property as necessary to accommodate its production needs. Except as otherwise agreed by both parties in the Lease Agreement, neither party may terminate the lease early during the lease term. Prime World holds additional rights under the Lease Agreement, including but not limited to: (i) the right of first refusal to purchase the Leased Property if the Lessor chooses to sell; (ii) the right to ensure that the Lease Agreement remains valid and binding on any purchaser in the event of a sale to a third party; (iii) the right of first refusal to renew the lease under the same terms offered to other prospective tenants; and (iv) protection against termination during the first eight years, with the Lessor required to provide twelve months’ prior written notice and payment of three months’ rent for termination from the ninth year onward. The foregoing description of the Lease Agreement does not purport to be a complete statement of the parties’ rights and obligations under the Lease Agreement and is qualified in its entirety by reference to the full text of the Lease Agreement, English translations of which are attached as Exhibit 10.1 to this Current Report on Form 8-K and incorporated by reference herein.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information contained in Item 1.01 of this Current Report on Form 8-K with respect to the Lease Agreement is incorporated by reference into Item 2.03.

Item 9.01 Financial Statements and Exhibits. (d) Exhibits 10.1 Translation of the Premises Lease Agreement, dated September 1, 2025, between Prime World International Holdings Ltd., Taiwan Branch and International Games System Co., Ltd. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── 104 Cover Page Interactive File (the cover page tags are embedded within the Inline XBRL document) 2 SIGNATURES