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            Applied Optoelectronics, Inc. 
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           (Name of Issuer) 
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            Common Stock 
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           (Title of Class of Securities) 
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           03823U102  
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           (CUSIP Number) 
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            May 31, 2024 
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           (Date of Event Which Requires Filing of this Statement) 
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           1 
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           NAMES OF REPORTING PERSONS 
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            DRIEHAUS CAPITAL MANAGEMENT LLC 
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           2 
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           CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 
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           (a)☐ 
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           (b)☐ 
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           3 
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           SEC USE ONLY 
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           4 
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           CITIZENSHIP OR PLACE OF ORGANIZATION 
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            Delaware, USA 
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           NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH 
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           5 
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           SOLE VOTING POWER 
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            0 
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           6 
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           SHARED VOTING POWER 
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            844,079 
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           7 
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           SOLE DISPOSITIVE POWER 
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            0 
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           8 
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           SHARED DISPOSITIVE POWER 
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            844,079 
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           9 
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           AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 
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           844,079 
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           10 
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           CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) 
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           ☐ 
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           11 
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           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 
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           2.17% 
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           12 
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           TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) 
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            IA 
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| Item 1(a). | Name of Issuer: | 
| Item 1(b). | Address of Issuer's Principal Executive Offices: | 
| Item 2(a). | Name of Person Filing: | 
| Item 2(b). | Address of Principal Business Office or, if none, Residence: | 
| Item 2(c). | Citizenship: | 
| Item 2(d). | Title of Class of Securities: | 
| Item 2(e). | CUSIP Number: | 
| Item 3. | If This Statement Is Filed Pursuant to Sections 240.13d-1(b) or | 
| (a) | ☐ Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o); | 
| (b) | ☐ Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c); | 
| (c) | ☐ Insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C. 78c); | 
| (d) | ☐ Investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8); | 
| (e) | ☒ Investment adviser in accordance with Section 240.13d-1(b)(1)(ii)(E); | 
| (f) | ☐ Employee benefit plan or endowment fund in accordance with Section 240.13d-1(b)(1)(ii)(F); | 
| (g) | ☐ Parent holding company or control person in accordance with Section 240.13d-1(b)(1)(ii)(G); | 
| (h) | ☐ Savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813); | 
| (i) | ☐ Church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3); | 
| (j) | ☐ A non-U.S. institution in accordance with Section 240.13d-1(b)(1)(ii)(J); | 
| (k) | ☐ Group, in accordance with Section 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Section 240.13d-1(b)(1)(ii)(J), please specify the type of institution: ____________________________ . | 
| Item 4. | Ownership. | 
| (a) | Amount beneficially owned: 844,079 | 
| (b) | Percent of class: 2.17% | 
            
| (c) | Number of shares as to which the person has: | 
| (i) | Sole power to vote or to direct the vote: 0 | 
            
| (ii) | Shared power to vote or to direct the vote: 844,079 | 
| (iii) | Sole power to dispose or to direct the disposition of: 0 | 
            
| (iv) | Shared power to dispose or to direct the disposition of: 844,079 | 
| Item 5. | Ownership of Five Percent or Less of a Class. | 
| Item 6. | Ownership of More Than Five Percent on Behalf of Another Person. | 
| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company. | 
| Item 8. | Identification and Classification of Members of the Group. | 
| Item 9. | Notice of Dissolution of Group. | 
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                 Item 10. 
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                 Certification. 
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           DRIEHAUS CAPITAL MANAGEMENT LLC 
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           By: 
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            /s/ Janet McWilliams 
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           Name:  Janet McWilliams 
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           Title:    General Counsel 
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