EXHIBIT 5.1


                       [Davis Polk & Wardwell Letterhead]


                                 650-752-2018


                                                            July 31, 2001

Re:  Registration Statement on Form S-8

Vitesse Semiconductor Corporation
741 Calle Plano
Camarillo, CA 93012


Ladies and Gentlemen:


     We are acting as counsel for Vitesse Semiconductor Corporation (the
"Company") in connection with the filing of a Registration Statement (the
"Registration Statement") on Form S-8 under the Securities Act of 1933, as
amended, relating to 1,093,877 shares of the Company's common stock, par value
$0.01 per share (the "Common Stock"), for options outstanding under the
Versatile Optical Networks, Inc. 2000 Stock Plan (the "Plan").

     We have examined originals or copies, certified or otherwise identified to
our satisfaction, of such documents, corporate records, certificates of public
officials and other instruments relating to the adoption of the Plan as we
have deemed necessary or advisable for the purposes of this opinion.

     Upon the basis of the foregoing, we are of the opinion that the Common
Stock deliverable pursuant to the Plan, when delivered in accordance with the
Plan upon receipt by the Company of adequate consideration therefor, will be
duly authorized, validly issued, fully paid and nonassessable.

     We consent to the filing of this opinion as Exhibit 5.1 to the Registration
 Statement.

                                               Very truly yours,

                                               /s/ Davis Polk & Wardwell