Item 1.01. Entry into a Material Definitive Agreement. On February 26, 2026, Applied Optoelectronics, Inc. (the “ Company”) entered into an Equity Distribution Agreement (the “ Agreement”) with Raymond James & Associates, Inc. and Needham & Company, LLC (collectively, the “ Sales Agents”) pursuant to which the Company may issue and sell shares of the Company’s common stock, par value $0.001 per share (the “ Shares”) having an aggregate offering price of up to $250 million from time to time through the Sales Agents. Upon delivery of a placement notice and subject to the terms and conditions of the Agreement, sales, if any, of the Shares will be made through the Sales Agents in transactions that are deemed to be “at the market” offerings as defined in Rule 415 of the Securities Act of 1933, as amended (the “ Securities Act”), including sales made through the facilities of the Nasdaq Global Market, the principal trading market for the Company’s common stock, on any other existing trading market for the Company’s common stock, to or through a market maker or as otherwise agreed by the Company and the Sales Agents. In the placement notice, the Company will designate the maximum number of Shares to be sold through the Sales Agents, the time period during which sales are requested to be made, the minimum price for the Shares to be sold, and any limitation on the number of Shares that may be sold in any one day. Subject to the terms and conditions of the Agreement, the Sales Agents will use their commercially reasonable efforts to sell Shares on the Company’s behalf up to the designated amount specified in the placement notice. The Company has no obligation to sell any Shares under the Agreement and may at any time suspend offers and sales of the Shares under the Agreement. The Agreement provides that the Sales Agents will be entitled to compensation of 2% of the gross sales price of the Shares sold through the Sales Agents from time to time. The Company has also agreed to reimburse the Sales Agents for certain specified expenses in connection with the registration of Shares under state blue sky laws and any filing with, and clearance of the offering by, the Financial Industry Regulatory Authority Inc., not to exceed $10,000 in the aggregate, and any associated application fees incurred. Additionally, if the Agreement is terminated under certain circumstances, and the Company fails to sell a minimum amount of the Shares as set forth in the Agreement, then the Company has agreed to reimburse the Sales Agents for reasonable out-of-pocket expenses, including the reasonable fees and disbursements of counsel incurred by the Sales Agents, up to a maximum of $30,000 in the aggregate. The Company agreed to indemnify the Sales Agents against certain liabilities, including liabilities under the Securities Act, or to contribute to payments that the Sales Agents may be required to make because of any of those liabilities. The offering pursuant to the Agreement will terminate upon the sale of all Shares subject to the Agreement. The Agreement may also be terminated by the Company or by the Sales Agents at any time. The Shares to be issued and sold have been registered under the Securities Act, pursuant to the Company’s automatic shelf registration statement on Form S-3ASR (Registration No. 333-283905), including the prospectus contained therein, as supplemented by the prospectus supplement filed with the Securities and Exchange Commission (the “ SEC”) pursuant to Rule 424(b) under the Securities Act on February 26, 2026. The foregoing description of the Agreement does not purport to be complete and is qualified in its entirety by reference to the complete text of the Agreement, which is filed as Exhibit 1.1 to this Current Report on Form 8-K and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits. (d) Exhibits.