APPLIED OPTOELECTRONICS, INC. — Major Shareholding Notification 2016

Feb 16, 2016

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G/A
Under the Securities Exchange Act of 1934
(Amendment No. 1)*
Applied Optoelectronics,
Inc.
(Name of Issuer)
Common stock,
$0.001 par value
(Title of Class of Securities)
03823U102
(CUSIP Number)
December
31, 2015
(Date of Event Which Requires Filing of This Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
¨	Rule 13d-1(b)
x	Rule 13d-1(c)
¨	Rule 13d-1(d)
(Page 1 of 16 Pages)

---

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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CUSIP No. 03823U102 13G/A Page 2 of 16 Pages

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1	NAME OF REPORTING PERSON Ardsley Partners Fund II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) x (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 496,800
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 496,800
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 496,800
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 3.0%
12	TYPE OF REPORTING PERSON PN

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| 1 | NAME OF REPORTING PERSON Ardsley Partners Institutional
Fund, L.P. | |
| --- | --- | --- |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP | (a) x (b) ¨ |
| 3 | SEC USE ONLY | |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION Delaware | |
| NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH: | 5 | SOLE VOTING POWER 0 |
| | 6 | SHARED VOTING POWER 403,200 |
| | 7 | SOLE DISPOSITIVE POWER 0 |
| | 8 | SHARED DISPOSITIVE POWER 403,200 |
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 403,200 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ¨ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 2.4% | |
| 12 | TYPE OF REPORTING PERSON PN | |

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| 1 | NAME OF REPORTING PERSON Ardsley Partners Advanced Healthcare
Fund, L.P. | |
| --- | --- | --- |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP | (a) x (b) ¨ |
| 3 | SEC USE ONLY | |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION Delaware | |
| NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH: | 5 | SOLE VOTING POWER 0 |
| | 6 | SHARED VOTING POWER 205,000 |
| | 7 | SOLE DISPOSITIVE POWER 0 |
| | 8 | SHARED DISPOSITIVE POWER 205,000 |
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 205,000 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ¨ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 1.2% | |
| 12 | TYPE OF REPORTING PERSON PN | |

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| 1 | NAME OF REPORTING PERSON Ardsley Partners US Equity UCITS
Fund plc | |
| --- | --- | --- |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP | (a) x (b) ¨ |
| 3 | SEC USE ONLY | |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION New York | |
| NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH: | 5 | SOLE VOTING POWER 0 |
| | 6 | SHARED VOTING POWER 0 |
| | 7 | SOLE DISPOSITIVE POWER 0 |
| | 8 | SHARED DISPOSITIVE POWER 0 |
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 0 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ¨ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 0% | |
| 12 | TYPE OF REPORTING PERSON PN | |

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| 1 | NAME OF REPORTING PERSON Ardsley Ridgecrest Partners Fund,
L.P. | |
| --- | --- | --- |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP | (a) x (b) ¨ |
| 3 | SEC USE ONLY | |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION New York | |
| NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH: | 5 | SOLE VOTING POWER 0 |
| | 6 | SHARED VOTING POWER 0 |
| | 7 | SOLE DISPOSITIVE POWER 0 |
| | 8 | SHARED DISPOSITIVE POWER 0 |
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 0 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ¨ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 0% | |
| 12 | TYPE OF REPORTING PERSON PN | |

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1	NAME OF REPORTING PERSON Ardsley Advisory Partners
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) x (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 1,105,000
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 1,105,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 1,105,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 6.6%
12	TYPE OF REPORTING PERSON PN; IA

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1	NAME OF REPORTING PERSON Ardsley Partners I
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) x (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 1,105,000
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 1,105,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 1,105,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 6.6%
12	TYPE OF REPORTING PERSON PN

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1	NAME OF REPORTING PERSON Philip J. Hempleman
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) x (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 50,000
	6	SHARED VOTING POWER 1,105,000
	7	SOLE DISPOSITIVE POWER 50,000
	8	SHARED DISPOSITIVE POWER 1,105,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY
EACH REPORTING PERSON 1,155,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT
IN ROW (9) 6.9%
12	TYPE OF REPORTING PERSON IN

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Item 1(a).
The name of the issuer is Applied Optoelectronics, Inc. (the " Company ").

Item 1(b).
The Company's principal executive offices are located at 13115 Jess Pirtle Blvd., Sugar Land, TX 77478.

Item 2(a).
This statement is filed by:

(i)	Ardsley Partners Fund II, L.P., a Delaware limited partnership (" AP II "), with respect to the Shares (as defined in Item 2(d) below) directly owned by it;
(ii)	Ardsley Partners Institutional Fund, L.P., a Delaware limited partnership (" Ardsley Institutional "), with respect to the Shares directly owned by it;
(iii)	Ardsley Partners US Equity UCITS Fund plc, an Irish UCITS plc (" Ardsley US Equity "), with respect to the Shares directly owned by it;
(iv)	Ardsley Partners Advanced Healthcare Fund, L.P., a Delaware limited partnership (" Ardsley Advanced "), with respect to the Shares directly owned by it;
(v) (vi) (vii)	Ardsley Ridgecrest Partners Fund, L.P., a Delaware
limited partnership (" Ardsley Ridgecrest "), with respect to the Shares directly owned by it; Ardsley Advisory Partners, a New York general
partnership (" Ardsley ") which serves as Investment Adviser of AP II, Ardsley Institutional, Ardsley Advanced and
Ardsley Ridgecrest and as Sub-Advisor of Ardsley US Equity, with respect to the Shares directly owned by AP II, Ardsley Institutional,
Ardsley US Equity, Ardsley Advanced and Ardsley Ridgecrest; Ardsley Partners I, a New York general partnership
(" Ardsley Partners ") which serves as General Partner of AP II, Ardsley Institutional, Ardsley Advanced and Ardsley
Ridgecrest, with respect to the Shares owned by AP II, Ardsley Institutional, Ardsley Advanced and Ardsley Ridgecrest; and
(viii)	Philip J. Hempleman (" Mr. Hempleman "), the Managing Partner of Ardsley and Ardsley Partners, with respect to the Shares owned by AP II, Ardsley Institutional, Ardsley US Equity, Ardsley Advanced, Ardsley Ridgecrest and with respect to the Shares owned by certain accounts managed by him directly.

The foregoing persons are hereinafter sometimes collectively referred to as the " Reporting Persons ." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. The filing of this statement should not be construed as an admission that any of the Reporting Persons is, for the purposes of Section 13(d) of the Act, the beneficial owner of the Shares reported herein.

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Item 2(b).
The address of the business office of each of the Reporting Persons is 262 Harbor Drive, Stamford, Connecticut 06902.

Item 2(c).
AP II, Ardsley Institutional, Ardsley Advanced and Ardsley Ridgecrest are Delaware limited partnerships. Ardsley US Equity is an Irish UCITS plc. Ardsley and Ardsley Partners are New York general partnerships. Mr. Hempleman is a United States citizen.

Item 2(d).
Common stock, par value $0.001 (the " Shares ")

Item 2(e).
03823U102

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO Rules 13d-1(b), OR 13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A:

(a)	¨	Broker or dealer registered under Section 15 of the Act;
(b)	¨	Bank as defined in Section 3(a)(6) of the Act;
(c)	¨	Insurance company as defined in Section 3(a)(19) of the Act;
(d)	¨	Investment company registered under Section 8 of the Investment Company Act of 1940;
(e)	¨	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
(f)	¨	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
(g)	¨	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);
(h)	¨	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;
(i)	¨	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;
(j)	¨	A non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);
(k)	¨	Group, in accordance with Rule 13d-1(b)(1)(ii)(K).

If filing as a non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J), please specify the type of institution: _________

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Item 4.
The information required by Items 4(a) – (c) is set forth in Rows 5-11 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each Reporting Person.
The percentages used in this Schedule 13G/A are calculated based upon 16,835,013 Shares reported to be outstanding as of November 3, 2015 in the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2015filed with the Securities and Exchange Commission on December 21, 2015. The percentages used herein and in the rest of the Schedule 13G/A are based upon such number of Shares outstanding.

Item 5.
Ardsley US Equity and Ardsley Ridgecrest no longer own any Shares.

Item 6.
Not applicable.

Item 7.
Not applicable.

Item 8.
Not applicable.

Item 9.
Not applicable.

ITEM 10. CERTIFICATION

Each of the Reporting Persons hereby makes the following certification:

By signing below each Reporting Person certifies that, to the best of his or its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

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SIGNATURES

After reasonable inquiry and to the best of his or its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

DATE: February 16, 2016

ARDSLEY PARTNERS FUND II, L.P.
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY: /s/ Steve Napoli
Steve Napoli
General Partner
ARDSLEY PARTNERS INSTITUTIONAL FUND, L.P.
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY: /s/ Steve Napoli
Steve Napoli
General Partner
Ardsley Partners US Equity UCITS Fund plc
BY: ARDSLEY ADVISORY PARTNERS
SUB-ADVISOR
BY: /s/ Steve Napoli
Steve Napoli
Partner
ARDSLEY PARTNERS ADVANCED HEALTHCARE FUND,
L.P. BY: PHILIP J. HEMPLEMAN GENERAL PARTNER
BY: /s/ Steve Napoli *
Steve Napoli
As attorney in fact for
Philip J. Hempleman
ARDSLEY RIDGECREST PARTNERS FUND, L.P
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY: /s/ Steve Napoli Steve Napoli General Partner

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ARDSLEY ADVISORY PARTNERS
BY: /s/ Steve Napoli Steve Napoli Partner
ARDSLEY PARTNERS I
BY: /s/ Steve Napoli Steve Napoli General Partner
PHILIP J. HEMPLEMAN, INDIVIDUALLY
BY: /s/ Steve Napoli *
Steve Napoli
As attorney in fact for
Philip J. Hempleman

• Evidence of Power of Attorney was filed with the Schedule 13G/A filed on February 15, 2006 (Acc-no: 0000902664-06-000895) and is incorporated by reference into this filing.

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EXHIBIT 1

JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G/A is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G/A shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein and therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

DATE: February 16, 2016

ARDSLEY PARTNERS FUND II, L.P.
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY: /s/ Steve Napoli
Steve Napoli
General Partner
ARDSLEY PARTNERS INSTITUTIONAL FUND, L.P.
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY : /s/ Steve Napoli
Steve Napoli
General Partner
Ardsley Partners US Equity UCITS Fund plc
BY: ARDSLEY ADVISORY PARTNERS
SUB-ADVISOR
BY: /s/ Steve Napoli
Steve Napoli
Partner
ARDSLEY PARTNERS ADVANCED HEALTHCARE FUND,
L.P. BY: PHILIP J. HEMPLEMAN GENERAL PARTNER
BY: /s/ Steve Napoli *
Steve Napoli
As attorney in fact for
Philip J. Hempleman

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ARDSLEY RIDGECREST PARTNERS FUND, L.P
BY: ARDSLEY PARTNERS I,
GENERAL PARTNER
BY: /s/ Steve Napoli Steve Napoli General Partner
ARDSLEY ADVISORY PARTNERS
BY: /s/ Steve Napoli Steve Napoli Partner
ARDSLEY PARTNERS I
BY: /s/ Steve Napoli Steve Napoli General Partner
PHILIP J. HEMPLEMAN, INDIVIDUALLY
BY: /s/ Steve Napoli *
Steve Napoli
As attorney in fact for
Philip J. Hempleman

• Evidence of Power of Attorney was filed with the Schedule 13G/A filed on February 15, 2006 (Acc-no: 0000902664-06-000895) and is incorporated by reference into this filing.