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                            JDS UNIPHASE CORPORATION
                              210 BAYPOINTE PARKWAY
                               SAN JOSE, CA 95134



                                                                     EXHIBIT 5.1

                             MORRISON & FOERSTER LLP
                            San Francisco, California

                                February 6, 2001

JDS Uniphase Corporation
210 Baypointe Parkway
San Jose, California 95134

Re:        Epion Corporation 1996 Stock Option Plan


Gentlemen:


         At your request, we have examined the Registration Statement on Form
S-8 (the "Registration Statement") executed by you on February 6, 2001, and to
be filed with the Securities and Exchange Commission (the "Commission") in
connection with the registration under the Securities Act of 1933, as amended
(the "Securities Act"), of an aggregate of 121,176 shares of your common
stock, $.001 par value (the "Common Stock"), which will be issuable under the
above-referenced plan (the "Plan").

         As your counsel in connection with the Registration Statement, we have
examined the proceedings taken by you in connection with the assumption of the
Plan by JDS Uniphase Corporation, and such documents as we have deemed necessary
to render this opinion, in connection with the acquisition of Epion Corporation
by JDS Uniphase Corporation.

         Based upon the foregoing, it is our opinion that the Common Stock, when
issued and outstanding pursuant to the terms of the Plan, will be validly
issued, fully paid and non-assessable.

         We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act. In giving such
consent, we do not hereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission.

                                      Very truly yours,


                                      /s/ Morrison & Foerster LLP
                                      ----------------------------
                                      MORRISON & FOERSTER LLP