<?xml version="1.0" encoding="US-ASCII" ?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 4.13b -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: http://www.novaworks.co -->
    <!-- Field: Doc-Info; Name: Source; Value: appliedopto_10q%2D20160331.xfr; Date: 2016%2D05%2D10T16:58:49Z -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
    <!-- Field: Doc-Info; Name: Misc; Value: 9ag5o7xRiXhun8uCZndcWaaNKcOdxZR/iZlBsGx5bQnqLykiBLCEDSvZ+fa2MTUN -->
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrldi="http://xbrl.org/2006/xbrldi" xmlns:dei="http://xbrl.sec.gov/dei/2014-01-31" xmlns:us-gaap="http://fasb.org/us-gaap/2016-01-31" xmlns:us-roles="http://fasb.org/us-roles/2016-01-31" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:us-types="http://fasb.org/us-types/2016-01-31" xmlns:AAOI="http://ao-inc.com/20160331" elementFormDefault="qualified" targetNamespace="http://ao-inc.com/20160331">
    <annotation>
      <appinfo>
	<link:roleType roleURI="http://ao-inc.com/role/DocumentAndEntityInformation" id="DocumentAndEntityInformation">
	  <link:definition>00000001 - Document - Document and Entity Information</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedBalanceSheets" id="CondensedConsolidatedBalanceSheets">
	  <link:definition>00000002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedBalanceSheetsParenthetical" id="CondensedConsolidatedBalanceSheetsParenthetical">
	  <link:definition>00000003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedStatementsOfOperations" id="CondensedConsolidatedStatementsOfOperations">
	  <link:definition>00000004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedStatementsOfComprehensiveIncomeLoss" id="CondensedConsolidatedStatementsOfComprehensiveIncomeLoss">
	  <link:definition>00000005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedStatementsOfStockholdersEquityDeficit" id="CondensedConsolidatedStatementsOfStockholdersEquityDeficit">
	  <link:definition>00000006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/CondensedConsolidatedStatementsOfCashFlows" id="CondensedConsolidatedStatementsOfCashFlows">
	  <link:definition>00000007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/DescriptionOfBusiness" id="DescriptionOfBusiness">
	  <link:definition>00000008 - Disclosure - 1. Description of Business</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/SignificantAccountingPolicies" id="SignificantAccountingPolicies">
	  <link:definition>00000009 - Disclosure - 2. Significant Accounting Policies</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/FairValueOfFinancialInstruments" id="FairValueOfFinancialInstruments">
	  <link:definition>00000010 - Disclosure - 3. Fair Value of Financial Instruments</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/EarningsPerShare" id="EarningsPerShare">
	  <link:definition>00000011 - Disclosure - 4. Earnings Per Share</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Inventories" id="Inventories">
	  <link:definition>00000012 - Disclosure - 5. Inventories</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/PropertyPlantAndEquipment" id="PropertyPlantAndEquipment">
	  <link:definition>00000013 - Disclosure - 6. Property, Plant and Equipment</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/IntangibleAssets" id="IntangibleAssets">
	  <link:definition>00000014 - Disclosure - 7. Intangible Assets</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/NotesPayableAndLong-termDebt" id="NotesPayableAndLong-termDebt">
	  <link:definition>00000015 - Disclosure - 8. Notes Payable and Long-Term Debt</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/AccruedLiabilites" id="AccruedLiabilites">
	  <link:definition>00000016 - Disclosure - 9. Accrued Liabilites</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/OtherIncomeAndExpense" id="OtherIncomeAndExpense">
	  <link:definition>00000017 - Disclosure - 10. Other Income and Expense</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensation" id="Share-basedCompensation">
	  <link:definition>00000018 - Disclosure - 11. Share-Based Compensation</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/StockholdersEquity" id="StockholdersEquity">
	  <link:definition>00000019 - Disclosure - 12. Stockholders' Equity</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/GeographicInformation" id="GeographicInformation">
	  <link:definition>00000020 - Disclosure - 13. Geographic Information</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/SubsequentEvents" id="SubsequentEvents">
	  <link:definition>00000021 - Disclosure - 14. Subsequent Events</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/DescriptionOfBusinessPolicies" id="DescriptionOfBusinessPolicies">
	  <link:definition>00000022 - Disclosure - 1. Description of Business (Policies)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/SignificantAccountingPoliciesPolicies" id="SignificantAccountingPoliciesPolicies">
	  <link:definition>00000023 - Disclosure - 2. Significant Accounting Policies (Policies)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/FairValueOfFinancialInstrumentsTables" id="FairValueOfFinancialInstrumentsTables">
	  <link:definition>00000024 - Disclosure - 3. Fair Value of Financial Instruments (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/EarningsPerShareTables" id="EarningsPerShareTables">
	  <link:definition>00000025 - Disclosure - 4. Earnings Per Share (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/InventoriesTables" id="InventoriesTables">
	  <link:definition>00000026 - Disclosure - 5. Inventories (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/PropertyPlantAndEquipmentTables" id="PropertyPlantAndEquipmentTables">
	  <link:definition>00000027 - Disclosure - 6. Property, Plant and Equipment (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/IntangibleAssetsTables" id="IntangibleAssetsTables">
	  <link:definition>00000028 - Disclosure - 7. Intangible Assets (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/NotesPayableAndLong-termDebtTables" id="NotesPayableAndLong-termDebtTables">
	  <link:definition>00000029 - Disclosure - 8. Notes Payable and Long-Term Debt (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/AccruedLiabilitesTables" id="AccruedLiabilitesTables">
	  <link:definition>00000030 - Disclosure - 9. Accrued Liabilites (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/OtherIncomeAndExpenseTables" id="OtherIncomeAndExpenseTables">
	  <link:definition>00000031 - Disclosure - 10. Other Income and Expense (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensationTables" id="Share-basedCompensationTables">
	  <link:definition>00000032 - Disclosure - 11. Share-Based Compensation (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/GeographicInformationTables" id="GeographicInformationTables">
	  <link:definition>00000033 - Disclosure - 13. Geographic Information (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/FairValueOfFinancialInstrumentsDetails" id="FairValueOfFinancialInstrumentsDetails">
	  <link:definition>00000034 - Disclosure - 3. Fair Value of Financial Instruments (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/EarningsPerShareDetails-epsCalculation" id="EarningsPerShareDetails-epsCalculation">
	  <link:definition>00000035 - Disclosure - 4. Earnings Per Share (Details-EPS calculation)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/EarningsPerShareDetails-PotentiallyDilutiveShares" id="EarningsPerShareDetails-PotentiallyDilutiveShares">
	  <link:definition>00000036 - Disclosure - 4. Earnings Per Share (Details - Potentially Dilutive Shares)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/InventoriesDetails" id="InventoriesDetails">
	  <link:definition>00000037 - Disclosure - 5. Inventories (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/InventoryDetailsNarrative" id="InventoryDetailsNarrative">
	  <link:definition>00000038 - Disclosure - 5. Inventory (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/PropertyPlantAndEquipmentDetails" id="PropertyPlantAndEquipmentDetails">
	  <link:definition>00000039 - Disclosure - 6. Property, Plant and Equipment (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/PropertyPlantAndEquipmentDetailsNarrative" id="PropertyPlantAndEquipmentDetailsNarrative">
	  <link:definition>00000040 - Disclosure - 6. Property, Plant and Equipment (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/IntangibleAssetsDetails" id="IntangibleAssetsDetails">
	  <link:definition>00000041 - Disclosure - 7. Intangible Assets (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/IntangibleAssetsDetailsNarrative" id="IntangibleAssetsDetailsNarrative">
	  <link:definition>00000042 - Disclosure - 7. Intangible Assets (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/NotesPayableAndLong-termDebtDetails" id="NotesPayableAndLong-termDebtDetails">
	  <link:definition>00000043 - Disclosure - 8. Notes Payable and Long-Term Debt (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/NotesPayableAndLong-termDebtDetails-DebtMaturities" id="NotesPayableAndLong-termDebtDetails-DebtMaturities">
	  <link:definition>00000044 - Disclosure - 8. Notes Payable and Long-Term Debt (Details - Debt maturities)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/NotesPayableAndLong-termDebtDetailsNarrative" id="NotesPayableAndLong-termDebtDetailsNarrative">
	  <link:definition>00000045 - Disclosure - 8. Notes Payable and Long-Term Debt (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/AccruedLiabilitiesDetails" id="AccruedLiabilitiesDetails">
	  <link:definition>00000046 - Disclosure - 9. Accrued Liabilities (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/OtherIncomeAndExpenseDetails" id="OtherIncomeAndExpenseDetails">
	  <link:definition>00000047 - Disclosure - 10. Other Income and Expense (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensationDetails-optionActivity" id="Share-basedCompensationDetails-optionActivity">
	  <link:definition>00000048 - Disclosure - 11. Share-Based Compensation (Details-Option activity)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensationDetails-restrictedStockUnits" id="Share-basedCompensationDetails-restrictedStockUnits">
	  <link:definition>00000049 - Disclosure - 11. Share-Based Compensation (Details-Restricted Stock Units)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensationDetails-shareBasedCompensationExpense" id="Share-basedCompensationDetails-shareBasedCompensationExpense">
	  <link:definition>00000050 - Disclosure - 11. Share-Based Compensation (Details-Share based compensation expense)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/Share-basedCompensationDetailsNarrative" id="Share-basedCompensationDetailsNarrative">
	  <link:definition>00000051 - Disclosure - 11. Share-Based Compensation (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/StockholdersEquityDetailsNarrative" id="StockholdersEquityDetailsNarrative">
	  <link:definition>00000052 - Disclosure - 12. Stockholders Equity (Details Narrative)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/GeographicInformationDetails-Revenues" id="GeographicInformationDetails-Revenues">
	  <link:definition>00000053 - Disclosure - 13. Geographic Information (Details - Revenues)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://ao-inc.com/role/GeographicInformationDetails-LongLivedAssets" id="GeographicInformationDetails-LongLivedAssets">
	  <link:definition>00000054 - Disclosure - 13. Geographic Information (Details - Long lived assets)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:linkbaseRef xlink:type="simple" xlink:href="aaoi-20160331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:title="Presentation Links" />
	<link:linkbaseRef xlink:type="simple" xlink:href="aaoi-20160331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:title="Label Links" />
	<link:linkbaseRef xlink:type="simple" xlink:href="aaoi-20160331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:title="Calculation Links" />
	<link:linkbaseRef xlink:type="simple" xlink:href="aaoi-20160331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:title="Definition Links" />
      </appinfo>
    </annotation>
    <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
    <import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
    <import namespace="http://xbrl.sec.gov/dei/2014-01-31" schemaLocation="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd" />
    <import namespace="http://fasb.org/us-gaap/2016-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd" />
    <import namespace="http://fasb.org/us-types/2016-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2016/elts/us-types-2016-01-31.xsd" />
    <import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" />
    <import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" />
    <import namespace="http://xbrl.sec.gov/country/2016-01-31" schemaLocation="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd" />
    <import namespace="http://xbrl.sec.gov/currency/2016-01-31" schemaLocation="http://xbrl.sec.gov/currency/2016/currency-2016-01-31.xsd" />
    <element id="AAOI_AdvancePayments" name="AdvancePayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_GovernmentSubsidyIncome" name="GovernmentSubsidyIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_CashRestrictedForConstructionInProgressFairValue" name="CashRestrictedForConstructionInProgressFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_BankAcceptanceReceivable" name="BankAcceptanceReceivable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_InterimFinancialStatementsPolicyTextBlock" name="InterimFinancialStatementsPolicyTextBlock" nillable="true" xbrli:periodType="duration" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageSharePriceOnDateOfExercise" name="WeightedAverageSharePriceOnDateOfExercise" nillable="true" xbrli:periodType="instant" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExcerciseWeightedAverageGrantDateFairValue" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExcerciseWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageFairValueVestedAndExpectedToVest" name="WeightedAverageFairValueVestedAndExpectedToVest" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedInPeriodTotalIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedInPeriodTotalIntrinsicValue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue2" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue2" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageFairValueVestedAndExpectedToVest2" name="WeightedAverageFairValueVestedAndExpectedToVest2" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageSharePriceOnDateOfRelease" name="WeightedAverageSharePriceOnDateOfRelease" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue1" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsExericsableWeightedAverageGrantDateFairValue1" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageFairValueVestedAndExpectedToVest1" name="WeightedAverageFairValueVestedAndExpectedToVest1" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueGranted" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueGranted" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueReleased" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueReleased" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueCancelled" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueCancelled" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_AggregateIntrinsicValueOtherThanOptionsExercisable" name="AggregateIntrinsicValueOtherThanOptionsExercisable" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_BankAcceptanceNotesPayableMember" name="BankAcceptanceNotesPayableMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_EastWestBankMember" name="EastWestBankMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_EastWestBankTermLoanMember" name="EastWestBankTermLoanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_EastWestBankConstructionLoanMember" name="EastWestBankConstructionLoanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_CTBCBankTaipeiMember" name="CTBCBankTaipeiMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ESunCommercialBankTaiwanMember" name="ESunCommercialBankTaiwanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_MegaInternationalCommercialBankTaiwanMember" name="MegaInternationalCommercialBankTaiwanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ChinaConstructionTaiwanMember" name="ChinaConstructionTaiwanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ChinaConstructionBankMember" name="ChinaConstructionBankMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving1Member" name="Revolving1Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving2Member" name="Revolving2Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_TermLoan1Member" name="TermLoan1Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_TermLoan2Member" name="TermLoan2Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving3Member" name="Revolving3Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving4Member" name="Revolving4Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving5Member" name="Revolving5Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Revolving6Member" name="Revolving6Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_NotePayable1Member" name="NotePayable1Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_NotePayable2Member" name="NotePayable2Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_EastWestBankTermLoan2Member" name="EastWestBankTermLoan2Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ChaileaseFinanceMember" name="ChaileaseFinanceMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ATMOfferingMember" name="ATMOfferingMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ConstructionLoanMember" name="ConstructionLoanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_NotePayable3Member" name="NotePayable3Member" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_Chailease2FinanceMember" name="Chailease2FinanceMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageSharesUsedToComputeNetIncomeLossPerShareAbstract" name="WeightedAverageSharesUsedToComputeNetIncomeLossPerShareAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_CashPaidFor" name="CashPaidFor" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_FairValueOfFinancialInstrumentsDetailsAbstract" name="FairValueOfFinancialInstrumentsDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_NumeratorAbstract" name="NumeratorAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_DenominatorAbstract" name="DenominatorAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_NetIncomeLossPerShare" name="NetIncomeLossPerShare" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_C.EarningsPerShareDetailsPotentiallyDilutiveSharesAbstract" name="C.EarningsPerShareDetailsPotentiallyDilutiveSharesAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_CurrencyDomain" name="CurrencyDomain" abstract="true" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_AccruedLiabilitiesDetailsAbstract" name="AccruedLiabilitiesDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_OtherIncomeAndExpenseDetailsAbstract" name="OtherIncomeAndExpenseDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_WeightedAverageFairValueAbstract" name="WeightedAverageFairValueAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_AggregateIntrinsicValueAbstract" name="AggregateIntrinsicValueAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValueGranted" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValueGranted" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="AAOI_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodTotalIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodTotalIntrinsicValue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
</schema>
