Finisar Corporation
FINISAR CORP (Form: SC 13G, Received: 11/13/2003 09:39:41)      
SECURITIES EXCHANGE COMMISSION

Washington, DC 20549

Under the Securities Exchange Act of 1934

FINISAR CORPORATION
(Name of Issuer)

Common
(Title of Class of Securities)

Date of Event Which Requires Filing of this Statement
November 13, 2003

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)

31787A101

(CUSIP NUMBER)


1) Name of Reporting Pioneer Global Asset Person Management S.p.A.

 

         IRS Identification                      13-1961193
         No. of Above

2)       Check the Appropriate Box               (a)
         of A Member of  Group
         (See Instructions)                      (b)  X

3)       SEC Use Only

4)       Citizenship of Place of
         Organization                            Italy

         Number of                               (5)  Sole Voting    12,980,114
         Shares                                  Power
         Beneficially Owned                      (6)  Shared Voting  0
         by Each Reporting                       Power
         Person With                             (7)  Sole Disposi-
                                                 tive Power          12,980,114
                                                 (8) Shared Disposi-
                                                 tive Power          0

9)      Aggregate Amount Beneficially           12,980,114
         Owned by Each
         Reporting Person

10)      Check if the aggregate
         Amount in Row  (9) Exclude Certain
         Shares (See
         Instructions)

11)      Percent of Class Represented
         By Amount in Row 9.                     5.75%

12)      Type of Reporting
         Person (See Instructions)               IA


Item 1(a) Name of Issuer.

FINISAR CORPORATION

Item 1(b) Address of Issuer's Principal Executive Offices:

1308 Moffett Park Drive
Sunnyvale, CA 84809

Item 2(a) Name of Person Filing:

Pioneer Global Asset Management S.p.A.

Item 2(b) Address of Principal Business Office:

Galleria San Carlo 6,
20122 Milan, Italy

Item 2(c) Citizenship:

Italy

Item 2(d) Title of Class of Securities:

Common Stock

Item 2(e) CUSIP Number:

31787A101

Item 3 The person filing this statement pursuant to Rule 13d-1(b)
or 13d-2(b) is:

(Inapplicable)


 
Item 4. Ownership.

(a) Amount Beneficially Owned: 12980114

(b) Percent of Class: 5.75%

(c) Number of shares as to which such person has

(i) sole power to vote or to direct the vote: 12,980,114

(ii) shared power to vote or to direct vote:     0

(iii) sole power to dispose or to direct
disposition of:                                 12,980,114

(iv) shared power to dispose or to
direct disposition                               0

Item 5. Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date Hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check here:

Item 6. Ownership of More than Five Percent on Behalf of Another Person.

Inapplicable.

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported On By the Parent Holding Company.

Inapplicable.

Item 8. Identification and Classification of Members of the Group.

Inapplicable.

Item 9. Notice of Dissolution of the Group.

Inapplicable.


Item 10. Certification.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transactions having such purposes or effect.

After reasonable inquiry and to the best of my knowledge and believe, I certify that the information set forth in this statement is true, complete and correct.

November 13, 2003
Date


/s/Dario Frigerio
Name: Dario Frigerio
Title: Chief Executive Officer