-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 dIjJERMseuVHRq5zULh4Cg==

<SEC-DOCUMENT>0001177261-04-000001.txt : 20041001
<SEC-HEADER>0001177261-04-000001.hdr.sgml : 20041001
<ACCEPTANCE-DATETIME>20041001115355
ACCESSION NUMBER:		0001177261-04-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040930
FILED AS OF DATE:		20041001
DATE AS OF CHANGE:		20041001

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CIENA CORP
		CENTRAL INDEX KEY:			0000936395
		STANDARD INDUSTRIAL CLASSIFICATION:	TELEPHONE & TELEGRAPH APPARATUS [3661]
		IRS NUMBER:				232725311
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		1201 WINTERSON ROAD
		CITY:			LINTHICUM
		STATE:			MD
		ZIP:			21090
		BUSINESS PHONE:		4108658500

	MAIL ADDRESS:	
		STREET 1:		1201 WINTERSON ROAD
		CITY:			LINTHICUM
		STATE:			MD
		ZIP:			21090

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BRADLEY STEPHEN P
		CENTRAL INDEX KEY:			0001177268

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21969
		FILM NUMBER:		041057192

	BUSINESS ADDRESS:	
		STREET 1:		HARVARD BUSINESS SCHOOL
		STREET 2:		MORGAN 237
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02163
		BUSINESS PHONE:		6174956344

	MAIL ADDRESS:	
		STREET 1:		HARVARD BUSINESS SCHOOL
		STREET 2:		MORGAN 237
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02163
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-09-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000936395</issuerCik>
        <issuerName>CIENA CORP</issuerName>
        <issuerTradingSymbol>CIEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001177268</rptOwnerCik>
            <rptOwnerName>BRADLEY STEPHEN P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>HARVARD BUSINESS SCHOOL</rptOwnerStreet1>
            <rptOwnerStreet2>MORGAN 237</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02163</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-09-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.995</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/Stephen Bradley by Anita Weiskerger per POA</signatureName>
        <signatureDate>2004-10-01</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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