<PAGE>

                                                                   Exhibit 10.13

                                    SUBLEASE

1.       PARTIES. This Sublease ("Sublease") dated March 1, 2000, is entered
into by and  between  Oplink ("Sublessee"), and Steag RTP Systems.
("Sublessor").

2. MASTER LEASE. Sublessor, as tenant, is leasing from Carlyle Fortran Trust,
a California limited partnership, as landlord ("Master Lessor"),
approximately 152,865 square feet of leasable area, consisting of the
following locations: 4425, 4423 and 4415 Fortran Court (comprising Buildings
B and C) in the City of San Jose, California (collectively, the "Premises"),
on the terms and subject to the conditions of that certain Lease Agreement
dated July 21, 1995 as modified by the First Amendment dated October 6, 1995
and the Second Amendment dated December 3, 1997 (collectively, "Master
Lease"). A copy of the Master Lease is attached hereto, marked Exhibit "A".
The Premises are located within a complex that includes the Premises and
related driveways, parking areas and appurtenant fixtures and improvements
(collectively, the "Property").

3.       PROVISIONS CONSTITUTING SUBLEASE.

         3.1       This Sublease is subject to all of the terms and
conditions of the Master Lease, except for those provisions of the Master
Lease that are directly contradicted by this Sublease in which event this
Sublease shall control over the Master Lease. Sublessee shall assume and
perform the obligations of Sublessor as lessee under the Master Lease to the
extent such terms and conditions are applicable to the Sublease Premises
(hereinafter defined). Subleassee shall not commit or permit to be committed
on the Sublease Premises any act or omission that shall violate any term or
condition of the Master Lease. Sublessor and Sublessee each agree that they
will not do, or permit their respective agents, employees or contractors to
do, anything which would constitute a violation or breach of any of the
terms, conditions or provisions of the Master Lease or which would cause the
Master Lease to be terminated or forfeited.

         3.2 Except for paragraphs 2, 3, 4.B, 4.E, 4P, 5, 7.D, 23, 25.C, 37,
39.B, 39.L, 40 and 41 of the original Lease Agreement; Exhibit "C" (Improvement
Agreement) to the original Lease Agreement; paragraphs 3, 4, and 5 of the First
Amendment; and paragraphs 2, 3, 4, 5, 6, 7, 10 and 11 of the Second Amendment,
all of the terms and conditions contained in the Master Lease are incorporated
herein as terms and conditions of this Sublease, and along with all of the
following paragraphs set forth herein shall be the complete terms and conditions
of this Sublease. All references in the Master Lease to the "Lease" or "lease"
shall be deemed to refer to this Sublease, all references in the Master Lease to
the "Premises" shall be deemed to refer only to the Sublease Premises hereunder,
and all references in the Master Lease to "Landlord" and "Tenant" shall be
deemed to refer to Sublessor and Sublessee, respectively, except that any
reference to "Landlord" in paragraphs 13 (except that Master Lessor shall retain
responsibility for making any alteration, addition or change to the Common Area
required by law as provided therein), 18, 19, 39.D, 39.G, 39.J shall be deemed
to refer to both Master Lessor and Sublessor, and any reference to "Landlord" in
paragraphs 8.C (except that Sublessee shall reimburse Sublessor for Sublessee's
Pro Rata Share of the cost of such insurance procured and maintained by Master
Lessor), 10.A, 10.B, 11, (except that Sublessee shall pay to Sublessor its Pro
Rata Share of Common Area Charges as provided in paragraph 12), 16, 21, 27, 28,
31.B, 32, 38 shall be deemed to refer to Master Lessor only. Notwithstanding
anything to the contrary contained


                                       1.
<PAGE>

herein, with respect to work, services, maintenance and repairs, or the
performance of other obligations required of Master Lessor under the Master
Lease, Sublessor shall be obligated to request the same, on request in
writing by Sublessee, and to use commercially reasonable efforts to obtain
the same from master Lessor. Sublessor shall cooperate with Sublessee as may
be required to obtain from Master Lessor any such work, services, maintenance
and repairs, or the performance of any of Master Lessor's other obligations
under the Master Lease.

4.       SUBLEASE PREMISES. Sublessor leases to Sublessee, and Sublessee
hires from said Sublessor, the premises consisting of approximately 38,284
square feet, situated in the City of San Jose, County of Santa Clara, State
of California, and located at 4415 Fortran Court (the "Sublease Premises") as
more particularly shown on Exhibit "B". The Sublease Premises constitutes a
portion of Building C referenced above (the "Building"). The rentable area of
the Sublease Premises is an estimate, subject to verification and amendment
by an architect mutually acceptable to the parties prior to the Commencement
Date, calculating the square footage on the basis of BOMA standard methods.
Any change in square footage (and resulting change in rent or Sublessee" Pro
Rata Share) shall be set forth in a written amendment to this Sublease signed
by both parties.

5.       TERM.

         5.1       COMMENCEMENT AND TERMINATION DATES. The term of this
Sublease shall be for the period of time commencing on March 15, 2000
("Commencement Date") and terminating on October 29, 2002, or on such earlier
date of termination as provided herein.

         5.2       EARLY ENTRY. Sublessor shall permit Sublessee to enter the
Sublease Premises prior to the Commencement Date in order to commence space
planning and design and to install Sublessee's furniture, cabling,
communication systems, equipment and furnishings, provided that such
occupancy shall be subject to all of the provisions of this Sublease,
excluding the Base Rent and Additional Rent. Early entry into the Sublease
Premises shall not advance the Termination Date. Sublessee shall, prior to
entering the Sublease Premises, deliver to Sublessor certificates of
insurance evidencing the policies required of Sublessee under this Sublease.
Notwithstanding the foregoing to the contrary, if Sublessor commences
business operations within the Sublease Premises prior to the Commencement
Date, then the Base Rent and Additional rent shall be payable from such
earlier date.

         5.3       CONDITION OF PREMISES. Sublessor and Sublessee agree that
the Subleased premises include existing interior improvements. Sublessee
hereby accepts the Sublease Premises in its "AS-IS" condition existing as of
the date Sublessee occupies the Sublease Premises, subject to all applicable
zoning, municipal, county and state laws, ordinances and regulations
governing and relating to the use of the Sublease Premises, and accepts this
Sublease subject thereto and to all matters disclosed thereby and by any
exhibits attached hereto. Sublessee acknowledges that neither Sublessor nor
Sublessee's agent, nor the Broker has made any representations or warranty as
to the suitability of the Sublease Premises for the conduct of Sublessee's
business.


                                       2.
<PAGE>

6.       RENT.

         6.1       RENT. Sublessee shall pay to Sublessor at the address
below as Base Rent, $47,855.00 per month. Delivered along with this Sublease
is Subleasee's check in the amount of $1,507,432.50, which is Sublessee's
rent obligation for the entire 31 1/2 month term of the Sublease.
Additionally, Sublessee shall pay to Sublessor Sublessee's Pro Rata Share of
the operating expenses for the building.

         6.2       OPERATING EXPENSES. In addition to the Base Rent,
Sublessee shall pay, as "Additional Rent," a proportionate share of all costs
and expenses which are defined as "Additional Rent" in Paragraph 4.D of the
Master Lease, and which are assessed to Sublessor under the Master Lease. As
used in this Sublease, the term "Sublessee's Pro Rata Share" shall mean a
fraction, expressed as a percentage, the numerator of which is the number of
square feet of floor space contained in the Sublease Premises and the
denominator of which is the number of square feet of floor space contained in
the Premises. As of the commencement date of this Sublease, Sublessee's Pro
Rata Share is 12.95%. Sublessee's Pro Rata Share may be revised from time to
time depending on any change in the square footage of the Premises.

7.       USE. The Premises shall be used and occupied only for office, R&D,
light manufacturing, distribution and warehousing, and for no other purpose.

8.       RIGHT OF FIRST REFUSAL. In the event the Sublessee is not in default
of this Sublease, Sublessee shall have a one-time right of first refusal to
lease the space at 4423 Fortran Drive comprising approximately 38,284 square
feet ("First Refusal Space"), subject to the approval of Master lessor, on
the same terms and conditions as contained in this Sublease, save that rent
shall be the then Fair Market Rental Rate, as defined below. Upon written
notice from the Sublessor of the availability of 4423 Fortran Drive,
Sublessee shall have five (5) days to exercise its right of first refusal,
whereupon Sublessor and Sublessee will enter into a new lease for the First
Refusal Space ("New Lease"). Promptly following the exercise of the right of
first refusal, the parties shall meet and endeavor to agree upon the Fair
Market Rental Rate of the First Refusal Space as of the first day of the New
Lease. If within thirty (30) days after the exercise of the right of first
refusal, the parties cannot agree in the Fair Market Rental Rate, the parties
shall submit the matter to binding appraisal in accordance with the following
procedure: Within sixty (60) days after exercise of the right of first
refusal, the parties shall either (a) jointly appoint an appraiser for this
purpose or (b) failing this joint action, separately designate a
disinterested appraiser. No person shall be appointed or designated an
appraiser unless he or she has at least five (5) years experience in
appraising major commercial property in Santa Clara County and is a member of
a recognized society of real estate appraisers. If, within thirty (30) days
after their appointment, the two appraisers reach agreement on the Fair
Market Rental Rate, that value shall be binding and conclusive upon the
parties. If the two appraisers thus appointed cannot reach agreement on the
question presented within thirty (30) days after their appointment, the
appraisers thus appointed shall appoint a third disinterested appraiser
having like qualifications. If within thirty (30) days after the appointment
of the third appraiser, a majority of the appraisers agree on the Fair Market
Rental Rate, that value shall be binding and conclusive upon the parties. If
within thirty (30) days after the appointment of the third appraiser, a
majority of the appraisers cannot reach agreement on the question presented,
then the three appraisers shall each submit their independent appraisal to
the parties, and the appraisal farthest from the median of the three


                                       3.
<PAGE>

appraisals shall be disregarded and the mean average of the remaining two
appraisals shall be deemed to be the Fair Market Rental Rate of the First
Refusal Space as of the first day of the New Lease and shall be binding and
conclusive upon the parties. Each party shall pay the fees and expenses of
the appraiser appointed by it and shall share equally the fees and expenses
of the third appraiser. If the two appraisers appointed by the parties cannot
agree on the appointment of the third appraiser, they or either of them shall
give notice of such failure to agree to the parties and if the parties fail
to agree upon the selection of such third appraiser within ten (10) days
after the appraisers appointed by the parties give such notice, then either
of the parties, upon notice to the other party may request such appointment
by the American Arbitration Association, or on its failure, refusal or
inability to act, may apply for such appointment to the presiding judge of
the Superior Court of Santa Clara County, California.

9.       BROKERS. Sublessor and Sublessee each represent to the other that
they have only dealt with Cushman & Wakefield of California, Inc.
("Sublessor's Broker") and Colliers International ("Sublessee's Broker") in
connection with this Sublease transaction. Sublessor and Sublessee shall each
indemnify, defend and hold the other harmless from and against any and all
liabilities or expenses, including attorneys' fees and costs, arising out of
or in connection with any claims for commissions or fees made by any other
broker or individual who represented or claims to have represented the
indemnifying party in connection with this Sublease.

10.      COMMISSION. Upon execution of this Sublease, Sublessor shall pay the
real estate commission for this transaction as agreed upon between Sublessor
and Sublessor's Broker per separate agreement.

11.      PARKING. Sublessee shall have the non-exclusive right to use
Sublessee's Pro Rata Share of the parking spaces in the Common Area as
designated from time to time by Master Lessor.

12.      COVENANT OF QUIET ENJOYMENT. Subject to the terms of this Sublease
and the Master Lease, Sublessor represents that if Sublessee performs all the
provisions in this Sublease to be performed by Sublessee, Sublessee shall
have and enjoy throughout the term of this Sublease the quiet and undisturbed
possession of the Premises.

13.      REPRESENTATIONS AND WARRANTIES OF SUBLESSOR. Sublessor represents
and warrants to Sublessee that as of the date of this Sublease, (i) the
Master lease is the entire agreement between Master Landlord and Sublessor
regarding the Premises, and the Master Lease has not been amended or modified
except as expressly set forth in this Sublease, (ii) Master Landlord and
Sublessor are not in breach or default of any of the provisions of the Master
lease, and (iii) the Master Lease is in full force and effect. At Sublessee's
request, Sublessor shall recertify each of the foregoing representations and
warranties as of the Commencement Date of this Sublease.

14.      NOTICES. Any notices required or desired to be given under this
Sublease shall be in writing, shall be personally served, delivered by
overnight courier, facsimile or United States registered or certified mail
and shall be addressed as set forth below. Any notice so given shall be
deemed to be delivered or made on (i) the date personal service is effected,
(ii) the same day if sent by facsimile transmission which if sender has
confirmation of successful transmission to


                                       4.
<PAGE>

recipient by 5:00 p.m. Pacific Standard Time, provided that a copy is
deposited in the United States mail, postage prepaid, (iii) the next business
day if sent by overnight courier or by facsimile transmission, or (iv) the
second business day after the same is deposited in the United States Mail as
registered or certified with postage thereon fully prepaid. Either party may
change its address by giving written notice thereof to the other in
accordance with the provisions of this paragraph. As of the date of this
Sublease, the addresses of the parties are as follows:

<TABLE>
<S>                          <C>                                   <C>                 <C>
         SUBLESSOR:            STEAG RTP Systems                       SUBLESSEE:
                               4425 Fortran Drive                                       --------------------------
                               San Jose, CA 95134-2300
                               Attn:  Ms. Anita Gat                                     --------------------------

                                                                                        --------------------------
                                                                                        Attn:
                                                                                              --------------------
</TABLE>

15.      MASTER LESSOR'S CONSENT. Sublessee acknowledges that this Sublease
is subject to the consent of Master Lessor under the Master Lease. Sublessor
shall use diligent efforts to obtain such consent as soon as reasonably
possible following execution of this Sublease by Sublessor and Sublessee.
Accordingly, this Sublease shall not be effective unless and until Master
Lessor's consent has been executed by Master Lessor. Sublessor shall have no
liability whatsoever to Sublessee, however, if Sublessor is unable to obtain
such consent from Master Lessor.

SUBLESSEE:                                        SUBLESSOR:
-----------------------------                     STEAG RTP SYSTEMS

By:   /s/ Joseph Liu                              By:    /s/ illegible
   --------------------------                        -------------------------
Title:    Joe Liu                                 Title:    President
      -----------------------                           ----------------------
Date:                                             Date:
     ------------------------                          -----------------------


                              MASTER LESSOR CONSENT

Consent by Master Lessor: The undersigned, Lessor under the Master Lease in
Exhibit "A", hereby consents to the subletting of the Premises described
herein on the terms and conditions contained in this Sublease. This consent
shall apply only to this Sublease and shall not be deemed to be a consent to
any other Sublease.

MASTER LESSOR:

By:
   -----------------------------
Title:
      --------------------------
Date:
     ---------------------------


                                       5.