<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-08-01</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0001056794</issuerCik><issuerName>AVANEX CORP</issuerName>        <issuerTradingSymbol>AVNX</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001237685</rptOwnerCik><rptOwnerName>BARBAROSSA GIOVANNI</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>40919 ENCYCLOPEDIA CIRCLE</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>FREMONT</rptOwnerCity><rptOwnerState>CA</rptOwnerState><rptOwnerZipCode>94538</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>CTO and V.P., Development</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Non-qualified Stock Option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>3.95</value></conversionOrExercisePrice><transactionDate><value>2003-08-01</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>200000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-08-01</value><footnoteId id="F1" /></exerciseDate><expirationDate><value>2013-07-31</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>200000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>200000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Non-qualified Stock Option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>1.975</value></conversionOrExercisePrice><transactionDate><value>2003-08-01</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>200000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-08-01</value><footnoteId id="F1" /></exerciseDate><expirationDate><value>2013-07-31</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>200000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>200000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">25% of the shares subject to the option shall vest and become exercisable on August 1, 2004, and 1/48 of the shares subject to the option shall vest each month thereafter, such that 100% of the shares subject to the option will be fully vested and exercisable on August 1, 2007.</footnote></footnotes><remarks></remarks><ownerSignature><signatureName>Anthony Florence, Attorney-in-fact for Giovanni Barbarossa</signatureName><signatureDate>2003-08-05</signatureDate></ownerSignature></ownershipDocument>

