EXHIBIT 8.1


                       [Kirkpatrick & Lockhart Letterhead]



December 12, 2001




MRV Communications, Inc.
20415 Nordhoff Street
Chatsworth, California 91311

Ladies and Gentlemen:

                  You have requested our opinion regarding certain Federal
income tax consequences of a series of transactions pursuant to which (i) MRV
Communications, Inc., a Delaware corporation ("MRV"), will transfer all of its
stock in Luminent, Inc., a Delaware corporation ("Luminent"), to MRV Merger Sub
Corp., a Delaware corporation and a wholly owned subsidiary of MRV (the "Merger
Sub"), and, thereafter, (ii) Luminent will merge with and into the Merger Sub,
with the Merger Sub surviving ((i) and (ii), collectively, the "Merger"). In the
Merger, each outstanding share of Luminent common stock (except for shares held
by Merger Sub, which will be cancelled, and shares held by Luminent stockholders
who perfect their statutory appraisal rights under Delaware law) will be
converted into shares of common stock of MRV.

                  In delivering this opinion, we have reviewed and relied upon
the Resolutions of the Boards of Directors of MRV and the Merger Sub approving
the Merger (the "Merger Resolutions"), the Prospectus included in the in the
post-effective amendments to the Registration Statement on Form S-4 (SEC file
no. 333-44536 (the "Prospectus") filed by the MRV with the Securities and
Exchange Commission (the "Commission") in connection with the Merger, and such
other documents pertaining to the Merger as we have deemed necessary or
appropriate. For purposes of this opinion, we have assumed (i) the validity and
accuracy of the documents that we have examined, (ii) that the Merger will be
consummated in the manner described in the Merger Resolutions and the
Prospectus, (iii) that all statements, descriptions and representations
contained in any of the documents referred to herein or otherwise made to us are
true and correct in all material respects and no actions have been (or will be)
taken that are inconsistent with such representations, and (iv) that the parties
to the Merger will report the Merger on their Federal income tax returns in a
manner consistent with the opinion set forth below. We have also relied upon
certificates of officers of MRV and the Merger Sub, respectively (the "Officers'
Certificates"), dated as of the date hereof. Unless otherwise defined,
capitalized terms referred to herein have the meanings set forth in the
Prospectus.

                  Based on our examination of the foregoing items and subject to
the assumptions, exceptions, limitations and qualifications set forth herein, we
are of the opinion that, if the Merger is consummated in accordance with the
Merger Resolutions and as described in the

MRV Communications, Inc.
December 12, 2001
Page 2

Prospectus (without any waiver, breach or amendment of any of the provisions
thereof), the statements set forth in the Officers' Certificates are true and
correct as of the date hereof and will continue to be true, correct and complete
as of the effective date of the Merger, then:

                           (a) The Merger will be treated for Federal income tax
purposes as a tax-free reorganization within the meaning of Section 368(a) of
the Internal Revenue Code of 1986, as amended ("Code");

                           (b) MRV, the Merger Sub and Luminent will each be a
"party to the reorganization" as defined in Section 368(b) of the Code; and

                           (c) The discussion set forth under the caption
"UNITED STATES FEDERAL INCOME TAX TREATMENT OF THE MERGER" in the Prospectus
insofar as it relates to statements of law or legal conclusions constitutes and
specifically represents our opinion with respect to such statements of law or
legal conclusions subject to the exceptions, limitations and caveats set forth
therein and herein.

                  This opinion represents and is based upon our best judgment
regarding the application of Federal income tax laws arising under the Code,
existing judicial decisions, administrative regulations and published rulings
and procedures. No assurance can be given that future legislative, judicial or
administrative changes would not adversely affect the accuracy of the
conclusions stated herein. We undertake no responsibility to advise you of any
new developments in the application or interpretation of the Federal income tax
laws.

                  This opinion addresses only the Federal income tax matters as
expressly set forth herein and does not address any other Federal, state, local
or foreign tax consequences that may result from the Merger or any other
transaction (including any transaction undertaken in connection with the
Merger).

                  We hereby consent to the discussion of this opinion in the
Prospectus, to the filing of this opinion as an exhibit to the Prospectus, and
to the reference to our firm under the headings "UNITED STATES FEDERAL INCOME
TAX TREATMENT OF THE MEGER" in the Prospectus. In giving such consent, we do not
thereby admit that we are in the category of persons whose consent is required
under Section 7 of the Securities Act of 1933, as amended, or the rules and
regulations of the Commission thereunder.


                                      Very truly yours,

                                      /s/ Kirkpatrick & Lockhart LLP

                                      KIRKPATRICK & LOCKHART LLP