Item 1.01 Entry into a Material Definitive Agreement. On October 28, 2025, Prime World International Holdings Ltd. (“ Prime World”), a wholly owned subsidiary of Applied Optoelectronics, Inc., entered into a new Premise Lease Agreement (the “ Lease Agreement”) with International Games System Co., Ltd. (the “ Lessor”). This Lease Agreement covers the property located at No. 49, Wugong 6th Road, Wugu District, New Taipei City (the “ Leased Property”), which constitutes the same premises as those covered under a prior lease agreement with Lessor dated September 1, 2025, pursuant to which Prime World currently leases a majority portion of the property. Under the Lease Agreement, Prime World will lease the remaining portion of the Leased Property, previously leased and occupied by another tenant, consisting of approximately 54,086 square feet. Upon execution of the Lease Agreement, Prime World will become the sole tenant of the entire Leased Property, enjoying full and exclusive rights of use and occupancy. The lease term will commence on December 1, 2025 and end on October 31, 2040, following a rent-free renovation period from November 1 to November 30, 2025. During the lease term, the monthly rent will increase by three percent (3%) approximately every five years. The monthly rent schedule is as follows: Period Monthly Rent ───────────────────────────────────────────────── December NTD 1,292,000 November NTD 1,330,760 November NTD 1,370,683 Under the Lease Agreement, Prime World may, at its own expense, make modifications to the building within the Leased Property as necessary to support its operational needs. Prime World holds certain additional rights under the Lease Agreement, including but not limited to: (i) a right of first refusal to purchase the Leased Property if the Lessor elects to sell; (ii) the right to ensure that the Lease Agreement remains valid and enforceable against any successor owner in the event of a sale; (iii) a right of first refusal to renew the lease on terms no less favorable than those offered to other prospective tenants; and (iv) protection against early termination during the first eight years of the lease, with any termination thereafter requiring the Lessor to provide at least twelve months’ prior written notice and payment of three months’ rent to Prime World. 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 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 Premise Lease Agreement, dated October 28, 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) 3 SIGNATURES