-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 EU7WzkqHmkrt0Q7RIozMCaxSDr6PhTnF+r1q3cMwxD8SPXG8O/n6FhiEVmB8ergQ
 aOcKoJT/7y4vJoFtjGPFBg==

<SEC-DOCUMENT>0000923328-03-000001.txt : 20030619
<SEC-HEADER>0000923328-03-000001.hdr.sgml : 20030619
<ACCEPTANCE-DATETIME>20030619163958
ACCESSION NUMBER:		0000923328-03-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030618
FILED AS OF DATE:		20030619

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CHANG MILTON PHD
		CENTRAL INDEX KEY:			0000923328

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-29811
		FILM NUMBER:		03750483

	BUSINESS ADDRESS:	
		STREET 1:		INCUBIC
		STREET 2:		855 MAUDE AVENUE
		CITY:			MOUNTAIN VIEW
		STATE:			CA
		ZIP:			94043

	MAIL ADDRESS:	
		STREET 1:		855 MAUDE AVENUE
		CITY:			MOUNTAIN VIEW
		STATE:			CA
		ZIP:			94043

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NEW FOCUS INC
		CENTRAL INDEX KEY:			0001090215
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				330404910
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		5215 HELLYER AVENUE STE 100
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			951381001
		BUSINESS PHONE:		4089808088

	MAIL ADDRESS:	
		STREET 1:		5215 HELLYER AVENUE STE 100
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			951381001
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-06-18</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001090215</issuerCik>
        <issuerName>NEW FOCUS INC</issuerName>
        <issuerTradingSymbol>NUFO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000923328</rptOwnerCik>
            <rptOwnerName>CHANG MILTON PHD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-18</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>S</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>30000</value>
            </transactionShares>
            <transactionValue>
                <value>4</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>4198119</value>
                <footnoteId id="F1"/>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>By Family Trust</value>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">3,914,292 shares held directly; 800,000 shares held by Chang Partners, a California Limited Partnership and 100,000 shares held by Rosalind and Milton Chang Foundation</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Milton Chang</signatureName>
        <signatureDate>2003-06-19</signatureDate>
    </ownerSignature>

</ownershipDocument>

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