<PAGE>

                                                                    EXHIBIT 10.7

                                     LEASE


LANDLORD:    BerCar II LLC, a Massachusetts limited liability company


TENANT:      Sycamore Networks, Inc., a Delaware Corporation


PREMISES:    10 Elizabeth Drive
             Chelmsford, Massachusetts


DATED:       DECEMBER 21, 1998


GARY BUCKMAN
244 1550
__________________
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                               TABLE OF CONTENTS

<TABLE>
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                                                                         ----
<S>                                                                      <C>
ARTICLE I - REFERENCE DATA............................................      1
     (A)    SUBJECTS REFERRED TO......................................      1
     (B)    EXHIBITS..................................................      2

ARTICLE II - PREMISES.................................................      2

ARTICLE III - TERM AND CONSTRUCTION...................................      3
     (A)    TERM                                                            3
     (B)    LANDLORD'S REQUIRED WORK..................................      3
     (C)    TENANT'S WORK.............................................      4
     (D)    GENERAL CONSTRUCTION PROVISIONS...........................      4

ARTICLE IV - LANDLORD'S COVENANTS.....................................      4
     (A)    LANDLORD'S COVENANTS DURING THE TERM: ....................      4
     (B)    INTERRUPTIONS.............................................      5

ARTICLE V - RENT......................................................      5
     (A)    FIXED RENT................................................      5
     (C)    ADDITIONAL RENT - OPERATING COSTS.........................      7
     (D)    ADDITIONAL RENT - ELECTRICITY AND GAS.....................      9

ARTICLE VI - TENANT'S COVENANTS.......................................      9

ARTICLE VII - DEFAULT.................................................     14
     (A)    EVENTS OF DEFAULT.........................................     14
     (B)    OBLIGATIONS THEREAFTER....................................     15

ARTICLE VIII - CASUALTY AND TAKING....................................     16
     (A)    CASUALTY AND TAKING.......................................     16
     (B)    RESERVATION OF AWARD......................................     17

ARTICLE IX - MORTGAGEE................................................     17
     (A)    SUBORDINATION TO MORTGAGES................................     17
     (B)    LIMITATION ON MORTGAGEE'S LIABILITY.......................     18
     (C)    NO RELEASE OR TERMINATION.................................     19

ARTICLE X - GENERAL PROVISIONS........................................     19
     (A)    CAPTIONS..................................................     19
     (B)    SHORT FORM LEASE..........................................     19
     (C)    RELOCATION................................................     19
     (D)    NOTICES...................................................     20
</TABLE>
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<TABLE>
<S>                                                                        <C>
     (E)    SUCCESSORS AND ASSIGNS....................................     20
     (F)    NO SURRENDER..............................................     21
     (G)    WAIVERS AND REMEDIES......................................     21
     (H)    SELF-HELP.................................................     22
     (I)    ESTOPPEL CERTIFICATE......................................     22
     (J)    WAIVER OF SUBROGATION.....................................     22
     (K)    BROKERS...................................................     23
     (L)    LANDLORD'S DEFAULTS.......................................     23
     (M)    EFFECTIVENESS OF LEASE....................................     24
     (N)    HAZARDOUS MATERIALS.......................................     24

ARTICLE XI - SECURITY DEPOSIT.........................................     25

ARTICLE XII - MODIFICATION............................................     25
</TABLE>

     EXHIBIT A    PLAN SHOWING TENANT'S SPACE
     EXHIBIT B    INTENTIONALLY OMITTED
     EXHIBIT C    INTENTIONALLY OMITTED
     EXHIBIT D    LANDLORD'S SERVICES
     EXHIBIT E    RULES AND REGULATIONS
     EXHIBIT F    LEGAL DESCRIPTION OF LOT
     EXHIBIT G    SIGN CRITERIA
<PAGE>

    Lease dated as of the 21st day of December, 1998, by and between BerCar II
LLC, a Massachusetts limited liability company, as landlord ("Landlord"), and
Sycamore Networks, Inc., a Delaware corporation, as tenant ("Tenant").

                                   ARTICLE I
                                REFERENCE DATA

1.  (A)  SUBJECTS REFERRED TO:

    Each reference in this lease to any of the following subjects shall be
construed to incorporate the data stated for that subject in this Section 1(A):

LANDLORD'S ADDRESS:  c/o Altid Enterprises
                     17 Monsignor O'Brien Highway
                     Cambridge, Massachusetts 02141-1877

TENANT'S ADDRESS:    Prior to Commencement Date:

                     2 Highwood Drive
                     Tewksbury, MA 01876

                     After Commencement Date:

                     10 Elizabeth Drive
                     Chelmsford, MA

BUILDING:            That certain building known or to be known as and numbered
                     10 Elizabeth Drive, Chelmsford, Massachusetts

RENTABLE FLOOR AREA OF TENANT'S SPACE:
                     APPROXIMATELY 34,579 SQUARE FEET

TOTAL RENTABLE FLOOR AREA OF THE BUILDING:
                     113,280 SQUARE FEET

DELIVERY DATE:       JANUARY 4, 1999

TERM:  THREE (3) YEARS FROM THE COMMENCEMENT DATE

FIXED RENT:

     DURING THE FIRST (1ST) YEAR OF THE TERM -- $224,763.50 PER ANNUM/$18,730.00
     PER MONTH; AND
<PAGE>

     DURING EACH YEAR OF THE BALANCE OF THE TERM -- $319,855.75 PER
     ANNUM/$26,654.65 PER MONTH

SECURITY DEPOSIT:    $92,000.00 REDUCED TO $46,000.00 PURSUANT TO ARTICLE XI

GUARANTOR:  N/A

PERMITTED USE:       OFFICE, LIGHT MANUFACTURING AND RESEARCH AND DEVELOPMENT

PUBLIC LIABILITY INSURANCE LIMITS:
                     BODILY INJURY:    $2,000,000
                     PROPERTY DAMAGE:  $  500,000

     (B)  EXHIBITS

     The exhibits listed below in this Section are incorporated in this lease by
reference and are to be construed as part of this lease:

     EXHIBIT A    Plan Showing Tenant's Space
     EXHIBIT B    Intentionally Omitted
     EXHIBIT C    Intentionally Omitted
     EXHIBIT D    Landlord's Services
     EXHIBIT E    Rules and Regulations
     EXHIBIT F    Legal Description Of Lot
     EXHIBIT G    Sign Criteria

                                  ARTICLE II
                                   PREMISES

2.   PREMISES

     Subject to and with the benefit of the provisions of this lease, Landlord
hereby leases to Tenant, and Tenant leases from Landlord, Tenant's space in the
Building, excluding exterior faces of exterior walls, all common facilities of
the Building and all building service fixtures and equipment serving
(exclusively or in common) other parts of the Building.  Tenant's space, with
such exclusions, is hereinafter referred to as "the demised premises".  Tenant
shall have, as appurtenant to the demised premises, the right to use in common
with others entitled thereto, subject to reasonable rules from time to time made
by Landlord of which Tenant is given notice: (a) the common facilities from time
to time included in the Building or on the parcel of land on which the Building
is located (said parcel being more particularly described in Exhibit F and being
hereafter referred to as "the Lot"), to the extent from

                                      -2-
<PAGE>

time to time designated by Landlord; (b) the building service fixtures and
equipment serving the demised premises; and (c) the common facilities from time
to time serving the Lot in common with other parcels of land, such as any so-
called access roads, retention ponds, sewer and utility lines and the like, all
to the extent from time to time designated by Landlord. Landlord reserves the
right from time to time (a) to install, repair, replace, use, maintain and
relocate for service to the demised premises and to other parts of the Building
or either, building service fixtures and equipment wherever located in the
Building, (b) to alter, relocate or eliminate any other common facility, and (c)
to increase and/or decrease the size of the Lot by the acquisition of adjacent
land and/or the disposition of any portions thereof. No such increase or
decrease shall be deemed to have occurred until Landlord shall give Tenant
notice thereof. Landlord warrants that there shall always be parking for at
least three and one half (3 1/2) cars per 1,000 square feet of rentable floor
area, subject, however, to takings by eminent domain. Landlord agrees that in
exercising its rights hereunder, it shall not unreasonably interfere with the
conduct of Tenant's business in the demised premises.

                                  ARTICLE III
                             TERM AND CONSTRUCTION

3.   (A)  TERM

     To have and to hold for a period of three (3) years ("the Term") commencing
on January 4, 1999 (being hereafter referred to as "the Commencement Date") and,
unless sooner terminated as provided herein, ending at the end of the
Approximate Term; provided that if the Term (calculated as aforesaid) would
expire prior to the last day of a calendar month, the Term shall be extended so
as to expire on the last day of such calendar month.

     (B)  LANDLORD'S REQUIRED WORK

     Tenant acknowledges that it has inspected the demised premises, and it is
understood and agreed that Tenant will accept the demised premises in their
existing physical condition, and Landlord shall be under no obligation to make
any repairs, alterations or improvements to the demised premises prior to or at
the commencement of the Term hereof or at any time thereafter, except as herein
specifically provided otherwise.  Landlord shall place the mechanical equipment
serving the demised premises (including the heating, ventilating and air
conditioning system) into good operating condition prior to delivery of the
demised premises to Tenant.  Landlord shall make all repairs necessary to the
demised premises to place same into compliance with law as of the delivery date.
Tenant shall be obligated to make all repairs necessary as a result of Tenant's
work in the demised premises or which may be required for Tenant to obtain a
certificate of occupancy.

                                      -3-
<PAGE>

     (C)  TENANT'S WORK

     Tenant shall perform, at its own cost and expense, any work required to
prepare the demised premises for Tenant's occupancy (pursuant to plans and
specifications approved by Landlord), and Tenant shall equip the demised
premises with all trade fixtures and personal property suitable or appropriate
to the regular and normal operation of the type of business in which Tenant is
engaged.  All such trade fixtures and personal property shall be of first-class
quality, consistent with the quality of existing improvements.  As an inducement
for Tenant to execute this lease and prepare the demised premises for Tenant's
occupancy, Landlord shall pay to Tenant the sum of $172,895.00.  So long as
Tenant shall not then be in default in the performance of its agreements
contained in this lease, Landlord shall pay said sum to Tenant upon the last to
occur of: (a) the tenth (10th) day after the receipt by Landlord of the rent
payable hereunder for the first full month of the Term of this lease; and (b)
the receipt by Landlord of waivers of liens from all contractors and
subcontractors supplying labor and/or material for Tenant's work.  It is
expressly understood and agreed that except for Tenant's signs and movable trade
fixtures, all of Tenant's work shall be the property of Landlord whether or not
the actual cost thereof shall exceed said sum.

     (D)  GENERAL CONSTRUCTION PROVISIONS

     All construction work required or permitted by this lease, whether by
Landlord or by Tenant, shall be done in a good and workmanlike manner and in
compliance with all applicable laws and all lawful ordinances, regulations and
orders of governmental authorities and insurance rating or inspection bureaus
having jurisdiction over the Building.  Either party may inspect the work of the
other at reasonable times and shall promptly give notice of observed defects.

                                  ARTICLE IV
                             LANDLORD'S COVENANTS

4.   (A)  LANDLORD'S COVENANTS DURING THE TERM:

     Landlord covenants during the Term:

     (1) To furnish, through Landlord's employees or independent contractors,
the services listed in Exhibit D; and

     (2) Except and otherwise provided in this lease, to make such repairs to
the roof, exterior walls (but not any windows, doors, window frames or door
frames), and common facilities of the Building and the Lot as may be necessary
to keep them in Serviceable condition.

                                      -4-
<PAGE>

     (B)  INTERRUPTIONS

     Landlord shall not be liable to Tenant for any compensation or reduction of
rent by reason of inconvenience or annoyance or for loss of business arising
from (a) power losses or shortages, or (b) the necessity of Landlord's entering
the demised premises for any of the purposes in this lease authorized, including
without limitation, for repairing or altering the demised premises or any
portion of the building or for bringing materials into and/or through the
demised premises in connection with the making of repairs or alterations.

     In case Landlord is prevented or delayed from making any repairs,
alterations or improvements or furnishing any service or performing any other
covenant or duty to be performed on Landlord's part, by reason of any cause
reasonably beyond Landlord's control, Landlord shall not be liable to Tenant
therefor, nor, except as expressly otherwise provided in Article VIII, shall
Tenant be entitled to any abatement or reduction of rent by reason thereof, nor
shall the same give rise to a claim in Tenant's favor that such failure
constitutes actual or constructive, total or partial, eviction from the demised
premises.  Landlord reserves the right to stop any service or utility system
when necessary in Landlord's opinion by reason of accident or emergency or until
necessary repairs have been completed.  Except in case of emergency repairs,
Landlord will give Tenant reasonable advance notice of any contemplated stoppage
and, in any event, Landlord will use reasonable efforts to avoid unnecessary
inconvenience to Tenant by reason thereof.  Landlord agrees that if there is a
stoppage of such service or utility system for more than ten (10) business days,
and if Tenant cannot reasonably conduct its business in the demised premises as
a result thereof, Fixed Rent shall thereafter abate until such service or
utility system is restored, or Tenant is again able reasonably to conduct its
business in the demised premises.

                                   ARTICLE V
                                     RENT

5.   (A)  FIXED RENT

     Tenant agrees to pay, without any offset or reduction whatever (except as
made in accordance with the express provisions of this lease), fixed monthly
rent equal to 1/12th of the Fixed Rent, such rent to be paid in equal
installments in advance on the first day of each calendar month included in the
Term commencing on February 1, 1999; and for any portion of a calendar month at
the end of the Term, a portion of such fixed monthly rent, prorated on a per
diem basis.  All payments of Fixed and additional rent shall be made in lawful
money of the United States and shall be made to Landlord and sent to Landlord
c/o Altid Enterprises, 17 Monsignor O'Brien Highway, Cambridge, Massachussetts
02141-1877, or to such other person and/or at such other address as Landlord may
from time to time designate.

                                      -5-
<PAGE>

     If any payment or rent or any other payment hereunder by Tenant to Landlord
shall not be paid within the applicable cure period, the same shall bear
Interest from the date when the Same was payable until the date paid at the
lesser of (a) the prime rate" then charged its most favored customers by Fleet
Bank, plus four percent (4%) per annum, or (b) the highest lawful rate of
interest which Landlord may charge to Tenant without violating any applicable
law ("the Lease Interest Rate").  Such interest shall constitute additional rent
payable hereunder.

     (B)  ADDITIONAL RENT - TAXES

     (1)  For the purposes of this Section, "Tax Year" shall mean the twelve-
month period in use in the Town of Chelmsford, Massachusetts for the purpose of
imposing ad valorem taxes upon real property.  In the event that said town of
Chelmsford changes the period of its tax year, "Tax Year" shall mean a twelve-
month period commencing on the first day of such new tax year, and each twelve-
month period commencing on an anniversary of such date during the Term of this
lease.  For purposes of this Section "the Property" shall mean the Lot and all
improvements thereon from time to time, including the Building; and "the Factor"
shall mean a fraction the numerator of which is the Rentable Floor Area of
Tenant's Space and the denominator of which is the Total Rentable Floor Area of
The Building.

     (2)  During the Term Tenant shall pay to Landlord, as additional rent, an
amount equal to the real estate taxes imposed with respect to the Property for
each Tax Year multiplied by the Factor, such amount to be apportioned on a per
diem basis for any fraction of a Tax Year contained within the Term.  Payment on
account of real estate taxes shall be paid, as part of Tenant's total rent,
monthly, and at the times and in the fashion herein provided for the payment of
Fixed Rent.  For an initial period from the Commencement Date until the  end of
the first full Tax Year in which the Term shall commence ("the full assessment
year"), the amount so to be paid shall be $2,478.17 per month being the monthly
payment fixed by Landlord on or about the Commencement Date.  Promptly after the
end of each Tax Year, Landlord shall make a determination of Tenant's share of
the real estate taxes upon the Property, and if the aforesaid payments
theretofore made for such Tax Year by Tenant exceed Tenant's share of such real
estate taxes, such overpayment shall be credited against the payments thereafter
to be made by Tenant pursuant to this Section (B) or refunded to tenant at the
end of the Term; and if Tenant's share of such real estate taxes for such Tax
Year is greater than such payments theretofore made on account for such Tax
year, tenant shall make a suitable payment to Landlord.  After the full
assessment year, the initial monthly payment on account of such real estate
taxes shall be replaced each year by a payment which is one-twelfth (1/12) of
Tenant's share of such real estate taxes for the immediately preceding Tax Year.
Appropriate adjustments shall be made in said monthly payment if the real estate
taxes upon the Property for the current Tax year shall be known prior to the end
of said Tax Year and/or if real estate taxes shall be payable to the taxing
authority in

                                      -6-
<PAGE>

installments, all to the end that as each payment of real estate taxes shall
become payable Landlord shall have received from Tenant payments sufficient in
amount to pay Tenant's share of the real estate tax payment then payable by
Landlord. Landlord shall within sixty (60) days following the end of any Tax
Year forward to Tenant a copy of the real estate tax bill together with
Landlord's computation of Tenant's share thereof.

     (3)  If Landlord shall receive any tax refund or rebate or sum in lieu
thereof with respect to any Tax Year, then out of any balance remaining thereof,
after deducting Landlord's expenses incurred in obtaining such refund, rebate or
other sum, Landlord shall pay to Tenant, provided that Tenant is not then in
default beyond any applicable cure period in the performance of any of its
obligations hereunder, an amount equal to such balance multiplied by the Factor
for such Tax Year; but in no event shall Landlord pay to Tenant out of such
refund, rebate or other sum for any Tax Year more than the amount paid by Tenant
to Landlord pursuant to this Section (B) for such Tax Year.

     (4)  Any betterment assessment, so-called "rent tax" or any other tax
levied or imposed by any governmental authority in addition to, in lieu of or as
a substitute for real estate taxes shall nevertheless be deemed to be real
estate taxes for the purpose of this Section (B). Furthermore, to the extent
that any equipment installed as part of the Property (e.g. heating or air
conditioning equipment) shall be classified as personal property for purposes of
taxation, any personal property taxes thereon shall be deemed to be real estate
taxes for purposes of this Section (B). Real estate taxes shall not include any
franchise, estate, inheritance, succession, capital levy or transfer tax of
Landlord, or any income tax of Landlord.

     (5)  In the event of any taking of the Building under circumstances whereby
this lease shall not terminate, the Factor shall be adjusted in order to reflect
any change in the Rentable Floor Area of Tenant's Space and/or the Total
Rentable Floor Area of The Building.

     (C)  ADDITIONAL RENT - OPERATING COSTS

     (1)  For the purposes of this Section, the following terms shall have the
following respective meanings:

     Operating Year:  Each successive fiscal year (as adopted by Landlord) in
which any part of the Term of this lease shall fall.

     Operating Expenses:  All expenses reasonably necessary and incurred by
Landlord in operating and maintaining the Building, the Lot and their
appurtenances, including but without limitation, premiums for insurance;
compensation and all fringe benefits, workmen's compensation insurance premiums
and payroll taxes paid

                                      -7-
<PAGE>

by Landlord to, for or with respect to all persons at or below the level of
building manager engaged in maintenance of the Building and Lot; steam, water,
sewer, electric, gas, telephone, and other utility charges not billed directly
to tenants by Landlord or the utility company; cost of repairs and replacements
to the Building and the Lot; cost of sweeping and cleaning the paved areas of
the Lot; cost of snow plowing or removal, or both, and care of landscaping;
payments to independent contractors under service contracts for any of the
foregoing services (which payments may be to affiliates of Landlord provided the
same are at competitive rates); all other reasonable and necessary expenses paid
in connection with the operation, maintenance, repair and replacement of the
Building and Lot, or either; and a supervisory fee equal to twenty-five percent
of all of the Operating Expenses for the Operating Year in question. Operating
Expenses shall also include the Building's share (as reasonably determined by
Landlord) of costs incurred by Landlord in operating maintaining, repairing,
insuring and paying real estate taxes upon any common facilities of the sort
described in clause (c) of the third sentence of Article II hereof. Operating
Expenses shall not include principal and interest payments on any loans of
Landlord, the cost of repairs covered by insurance proceeds, or brokerage fees
or attorneys' fees incurred in negotiating leases for empty space at the
Building. Further, whenever Landlord shall make any necessary repair or
replacement which shall be deemed to be a "capital item" pursuant to generally
accepted accounting principals, then the cost thereof shall be amortized on a
straight line basis over such item's useful life as determined by generally
accepted accounting principles and, the costs and expenses to which Tenant shall
contribute each year shall include only such year's allocable portion of the
amount of said capital item.

     The Factor: As defined in Section (B) above.

     (2)  During the Term Tenant shall pay to Landlord, as additional rent, an
amount equal to the Operating Expenses for each Operating Year multiplied by the
Factor, such amount to be apportioned on a per diem basis for any fraction of an
Operating Year contained within the Term.  Payment on account of Tenant's share
of Operating Expenses shall be paid, as part of Tenant's total rent, monthly,
and at the times and in the fashion herein provided for the payment of Fixed
Rent.  For an initial period from the Commencement Date until the end of the
Operating Year during which the Term shall commence, the amount so to be paid
shall be $2,190.00 per month being the monthly payment fixed by Landlord on or
about the Commencement Date.  Promptly after the end of said partial Operating
Year and promptly after the end of each Operating Year thereafter, Landlord
shall make a determination of Tenant's share of said Operating Expenses; and if
the aforesaid payments theretofore made for such period by Tenant exceed
Tenant's share, such overpayment shall be credited against the payments
thereafter to be made by Tenant pursuant to this Section (C) or refunded to
Tenant at the expiration of the Term; and if Tenant's share is greater than such
payments theretofore made on account for such period, Tenant shall make a
suitable payment to Landlord.  The initial monthly

                                      -8-
<PAGE>

payment on account of Operating Expenses shall be replaced after Landlord's
determination of Tenant's share thereof for the preceding Operating Year by a
payment which is one-twelfth (1/12) of Tenant's actual share thereof for the
immediately preceding Operating Year, with adjustments as appropriate where such
Operating Year is less than a full twelve-month period. Landlord agrees that
upon the request of Tenant it will give Tenant a copy of the invoices evidencing
said Operating Expenses together with a statement in reasonable detail computing
Tenant's share thereof.

     (3)  In the event of any taking of the Building under circumstances whereby
this lease shall not terminate, the Factor shall be appropriately adjusted to
reflect any change in the Rentable Floor Area of Tenant's Space and/or the Total
Rentable Floor Area of The Building.

     (D)  ADDITIONAL RENT - ELECTRICITY AND GAS

     (1)  The demised premises shall have an electric meter measuring the
electricity consumed in the demised premises and a gas meter measuring the gas
consumed therein.  Commencing upon Tenant's entry into the demised premises to
perform Tenant's work, Tenant shall pay to the utility companies furnishing such
electricity and gas, promptly upon the receipt of bills therefor, the cost of
all electricity and gas consumed in the demised premises.

     (2)  Tenant's use of electricity in the demised premises shall not at any
time exceed the capacity of any of the electrical conductors or equipment in or
otherwise serving the demised premises.

                                  ARTICLE VI
                             TENANT'S COVENANTS

6.   TENANT'S COVENANTS DURING THE TERM.

     Tenant covenants during the Term and such other time as Tenant occupies any
part of the demised premises:

     (1)  To pay when due (a) all Fixed Rent and additional rent, (b) all taxes
which may be imposed on Tenant's personal property in the demised premises
(including, without limitation, Tenant's fixtures and equipment) regardless to
whomever assessed, and (c) all charges by any public utility for telephone and
other utility services rendered to the demised premises but which are not made
Landlord's responsibility in Section (D) of Article V hereof.  Tenant shall
provide adequate heat to the demised premises to prevent the freezing and/or
bursting of any pipes or duct work therein;

                                      -9-
<PAGE>

     (2)  Except as otherwise provided in Article VIII and Subsection (2) of
Section (A) of Article IV, to keep the demised premises in good order, repair
and condition, reasonable wear only excepted; and at the expiration or
termination of this lease peaceably to yield up the demised premises and all
changes and additions therein in such order, repair and condition, first
removing all goods and effects of Tenant and those claiming under Tenant and any
items the removal of which is required by any agreement between Landlord and
Tenant (or specified therein to be removed at Tenant's election and which Tenant
elects to remove), and repairing all damage caused by such removal and restoring
the demised premises and leaving them clean and neat.  Notwithstanding anything
to the contrary contained herein, Tenant shall forthwith remove from the demised
premises (repairing any damage caused by such removal) any installations,
alterations, additions or improvements made by Tenant or Landlord including,
without limitation, any installations, alterations, additions or improvements
made as part of Landlord's Required Work or as part of Tenant's work, and which
Landlord requests Tenant to remove at the time Tenant obtains Landlord's
approval for the installation of same, such removal to include returning the
previously modified portions of the demised premises to their condition prior to
the making of such installations, alterations, additions or improvements.
Tenant's obligations hereunder shall survive the expiration or termination of
the term of this lease.  For purposes of this Section (2) the word "repairs"
includes the making of replacements when necessary.

     (3)  To use and occupy the demised premises only for the Permitted Use; and
not to injure or deface the demised premises, Building, or Lot; and not to
permit in the demised premises any auction sale, nuisance, or the emission from
the demised premises of any objectionable noise or odor; nor any use thereof
which is improper, offensive, contrary to law or ordinances, or liable to
invalidate or increase the premiums for any insurance on the Building (or any
portion thereof) or its contents, or liable to render necessary any alteration
or addition to the Building;

     (4)  To comply with the rules and regulations set forth in Exhibit E and
all other reasonable rules and regulations hereafter made by Landlord (but only
after copies thereof have been delivered to Tenant) for the care and use of the
Building and Lot and their facilities and approaches, it being expressly
understood, however, that Landlord shall not be liable to Tenant for the failure
of other tenants of the Building to conform to such rules and regulations.
Landlord agrees that it shall not discriminate against Tenant in enforcing said
rules and regulations;

     (5)  To keep the demised premises equipped with all safety appliances
required by law or ordinance or any other regulation of any public authority
and/or any insurance inspection or rating bureau having jurisdiction, and to
procure all licenses and permits required because of any use made by Tenant and,
if requested by Landlord, to do any work required because of such use, it being
understood that the foregoing provisions shall not be construed to broaden in
any way the Permitted

                                     -10-
<PAGE>

Use.  Landlord agrees that the demised premises shall be
delivered in compliance with applicable law.  If any work is required in order
for Tenant to obtain a building permit and as a direct consequence of Tenant's
work, Tenant shall perform all such work at Tenant's cost and expense;

     (6)  Not without the prior written consent of Landlord to assign,
hypothecate, pledge or otherwise encumber this lease, to make any sublease or to
permit occupancy of the demised premises or any part thereof by anyone other
than Tenant, voluntarily or by operation of law, and as additional rent, to
reimburse Landlord promptly upon demand for reasonable legal and other expenses
incurred by Landlord in connection with any request by Tenant for consent to
assignment or subletting.  Without intending to limit Landlord's discretion in
granting or withholding such consent, it is agreed that if Tenant requests
Landlord's consent to assign this lease or sublet more than thirty five percent
(35%) of the demised premises, Landlord shall have the option, exercisable by
written notice to Tenant given within sixty days after receipt of such request,
to terminate this lease as of a date specified in such notice which shall be not
less than thirty or more than sixty days after the date of such notice.  If
Landlord shall so terminate this lease, rent shall be apportioned as of the date
of termination, and Landlord may lease the demised premises or any part thereof
to any person or entity (including without limitation, Tenant's proposed
assignee or subtenant, as the case may be) without any liability whatsoever to
Tenant by reason thereof.  If Landlord shall consent to any assignment of this
lease by Tenant or a subletting of the whole of the demised premises by Tenant
at a rent which exceeds the rent payable hereunder by Tenant, or if Landlord
shall consent to a subletting of a portion of the demised premises by Tenant at
a rent in excess of the subleased portion's pro rata share of the rent payable
hereunder by Tenant, then Tenant shall pay to Landlord, as additional rent
forthwith upon Tenant's receipt of each installment of any such excess rent,
half (1/2) the amount of any such excess rent.  Each request by Tenant for
permission to assign this lease or to sublet the whole or any part of the
demised premises shall be accompanied by a warranty by Tenant as to the amount
of rent to be paid to Tenant by the proposed assignee or sublessee.  For
purposes of this Section (6), the term "rent" shall mean all fixed rent,
additional rent or other payments and/or consideration payable by one party to
another for the use and occupancy of premises.  Tenant agrees, however, that
neither it nor anyone claiming under it shall enter into any sublease, license,
concession or other agreement for use, occupancy or utilization

                                     -11-
<PAGE>

of space in the demised premises which provides for rental or other payment for
such use, occupancy or utilization based, in whole or in part, on the net income
or profits derived by any person or entity from the space leased, used, occupied
or utilized (other than an amount based on a fixed percentage or percentages of
receipts or sales), and Tenant agrees that any such purported sublease, license,
concession or other agreement shall be absolutely void and ineffective as a
conveyance of any right or interest in the possession, use, occupancy, or
utilization of any part of the demised premises. Tenant further agrees that any
sublease, license, concession or agreement for use, occupancy or utilization of
space in the demised premises entered into by it or by anyone claiming under it
shall contain the provisions set forth in the immediately preceding sentence.
Landlord hereby agrees, however, that Tenant may assign its interest in this
lease or sublet the whole of the demised premises to (a) an entity which owns
all of the outstanding stock of Tenant ("Tenant's Parent"); (b) an entity wholly
owned by Tenant or by Tenant's Parent ("a Subsidiary"); (c) an entity resulting
from the consolidation or merger of Tenant with any other entity; or (d) an
entity to whom Tenant shall sell all or substantially all of Tenant's assets or
stock. Notwithstanding the foregoing provisions, if the assignment or subletting
is to a Subsidiary, said assignment or subletting shall be valid only for such
period of time as said Subsidiary is wholly owned by Tenant or Tenant's Parent.
In the event that Tenant or Tenant's Parent shall ever sell or otherwise
transfer any interest in said Subsidiary to another person or entity, unless
Landlord shall have specifically assented thereto the same shall be deemed to be
a material breach of this lease.

     (7)  To defend Landlord with counsel reasonably acceptable to Landlord,
save Landlord harmless from, and indemnify Landlord against any liability for
injury, loss, accident or damage to any person or property and from any claims,
actions, proceedings and expenses and costs in connection therewith (including,
without implied limitation, reasonable counsel's fees): (i) arising from the
omission, fault, wilful act, negligence or other misconduct of Tenant or anyone
claiming under Tenant, or from any use made or thing done or occurring upon or
about the demised premises but not due to the omission, fault, willful act,
negligence or other misconduct of Landlord, or (ii) resulting from the failure
of Tenant to perform and discharge its covenants and obligations under this
lease;

     (8)  To maintain public liability insurance upon the demised premises in
amounts which shall, at the beginning of the Term, be at least equal to
$2,000,000.00 for bodily injury or death to one or more individuals and
$500,000.00 for damage to property, and from time to time during the Term, shall
be for such higher limits, if any, as are customarily carried in the area in
which the demised premises are located upon property similar in type and use to
the demised premises.  Such insurance shall name Landlord as an additional
insured.  Tenant shall deliver to Landlord the policies of such insurance, or
certificates thereof, at least fifteen (15) days prior to the Commencement Date,
and each renewal policy or certificate thereof, at least fifteen (15) days prior
to the expiration of the policy it renews.  Each such policy shall be written by
a responsible insurance company authorized to do business in the state in which
the Building is located and shall provide that the same shall not be modified or
terminated without at least twenty (20) days' prior written notice to each named
insured;

     (9)  To keep all employees working in the demised premises covered by
workmen's compensation insurance in amounts required by law, and to furnish
Landlord with certificates thereof;

                                     -12-
<PAGE>

     (10) To permit Landlord and its agents entry upon reasonable prior notice
and during normal business hours (except in the case of an emergency, when
Landlord may enter at any time), to examine the demised premises at reasonable
times and, if Landlord shall so elect, to make repairs, alterations and
replacements; to remove, at Tenant's expense, any changes, additions, signs,
curtains, blinds, shades, awnings, aerials, flagpoles, or the like not consented
to in writing; and to show the demised premises to prospective tenants during
the twelve (12) months preceding the expiration of the Term and to prospective
purchasers and mortgagees at all reasonable times;

     (11) Not to place a load upon any part of the floor of the demised premises
exceeding that for which said floor was designed or in violation of what is
allowed by law; and not to move any safe, vault or other heavy equipment in,
about or out of the demised premises except in such manner and at such times as
Landlord shall approve in writing in each instance.  Tenant's business machines
and mechanical equipment which cause vibration or noise that may be transmitted
to the Building structure or to any other space in the Building shall be placed
and maintained by Tenant in settings of cork, rubber, spring, or other types of
vibration eliminators sufficient to confine such vibration or noise to the
demised premises;

     (12) All the furnishings, fixtures, equipment, effects and property of
every kind, nature and description of Tenant and of all persons claiming by,
through or under Tenant which, during the continuance of this lease or any
occupancy of the demised premises by Tenant or anyone claiming under Tenant, may
be on the demised premises or elsewhere in the Building or on the Lot shall be
at the sole risk and hazard of Tenant, and if the whole or any part thereof
shall be destroyed or damaged by fire, water or otherwise, or by the leakage or
bursting of water pipes, steam pipes, or other pipes, by theft, or from any
other cause, no part of said loss or damage is to be charged to or to be borne
by Landlord, unless caused by negligence or willful misconduct of Landlord, its
agents, servants, contractors or employees;

     (13) To pay promptly when due the entire cost of any work done on the
demised premises by Tenant and those claiming under Tenant; not to cause or
permit any liens for labor or material performed or furnished in connection
therewith to attach to the demised premises; and to discharge within thirty (30)
days any such liens which may so attach;

     (14) Not to make any alterations, improvements, changes or additions to the
demised premises without Landlord's prior written consent.  Landlord hereby
approves the making by Tenant of interior alterations to the demised premises
provided same (i) do not affect the structure of the demised premises or the
Building which contains the demised premises; and (ii) do not affect the common
utility lines or other mechanical systems of the Building which includes the
demised premises;

                                     -13-
<PAGE>

     (15) To pay to Landlord two (2) times the total of the Fixed Rent and
additional rent then applicable for each month or portion thereof that Tenant
shall retain possession of the demised premises or any part thereof after the
termination  this lease, whether by lapse of time or otherwise, and also to pay
all damages sustained by Landlord on account thereof; however, the provisions of
this subsection shall not operate as a waiver by Landlord of any right of re-
entry provided in this lease or as a matter of law;

     (16) To insure the contents, equipment, and improvements of Tenant and
those claiming under Tenant, under policies covering at least fire and the
standard extended coverage risks, in amounts equal to the replacement cost
thereof, the terms of which policies shall provide that such insurance shall not
be canceled without at least twenty (20) days' prior written notice to Landlord.
Copies of such insurance policy or policies, or certificates there of, shall be
delivered to Landlord at least fifteen (15) days prior to the Commencement Date
and each renewal policy or certificate thereof, at least fifteen (15) days prior
to the expiration of the policy it renews;

     (17) The losing party shall pay the other party's expenses, including
reasonable attorney's fees, incurred in enforcing any obligation of the losing
party in this lease; and

     (18) To obtain and maintain in full force and effect a heating and air
conditioning equipment service contract which shall provide for the periodic
inspection and maintenance of the heating and air conditioning equipment
servicing the demised premises.  Said contract shall be made with a reputable
contractor and shall be subject to Landlord's approval, which approval Landlord
agrees not unreasonably to withhold.  Copies of said contract and any renewals
and/or replacements thereof shall be delivered to Landlord.

                                  ARTICLE VII
                                    DEFAULT

7.   (A)  EVENTS OF DEFAULT

     (1)  If Tenant shall default in the payment of Fixed Rent, additional rent
or other payments required of Tenant, and if Tenant shall fail to cure said
default within ten (10) days after receipt of notice of said default from
Landlord, or (2) if Tenant shall default in the performance or observance of any
other agreement or condition on its part to be performed or observed and if
Tenant shall fail to cure said default within thirty (30) days after receipt of
notice of said default from Landlord (but if longer than thirty (30) days shall
be reasonably required to cure said default, then if Tenant shall fail to
commence the curing of such default within thirty (30) days after receipt of
said notice and diligently prosecute the curing thereof to completion), or (3)

                                     -14-
<PAGE>

if any persons shall levy upon, or take this leasehold interest or any part
thereof upon execution, attachment or other process of law, or (4) if Tenant or
Guarantor shall make an assignment of its property for the benefit of creditors,
or (5) if Tenant or Guarantor shall be declared bankrupt or insolvent according
to law, or (6) if any bankruptcy or insolvency proceedings shall be commenced by
or against Tenant or Guarantor and, if against, if not discharged within sixty
(60) days, (7) if a receiver, trustee or assignee shall be appointed for the
whole or any part of Tenant's or Guarantor's property, or (8) if the letter of
credit is not renewed, and not replaced within five (5) days of notification of
nonrenewal, then in any of said cases, Landlord lawfully may immediately, or at
any time thereafter, and without any further notice or demand, enter into and
upon the demised premises or any part thereof in the name of the whole, by force
or otherwise, and hold the demised premises as if this lease had not been made,
and expel Tenant and those claiming under it and remove its or their property
(forcibly, if necessary) without being taken or deemed to be guilty of any
manner of trespass (or Landlord may send written notice to Tenant of the
termination of this lease), and upon entry as aforesaid (or in the event that
Landlord shall send Tenant notice of termination as above provided, on the fifth
day next following the date of the sending of the notice), the term of this
lease shall terminate.  Notwithstanding the provisions of clauses (1) and (2) of
the immediately preceding sentence, if Landlord shall have rightfully given
Tenant notice of default pursuant to either or both of said clauses twice during
any twelve-month period, and if Tenant shall thereafter default in the payment
of Fixed Rent, additional rent or other payments and/or the performance or
observance of any other agreement or condition required of Tenant, then Landlord
may exercise the right of termination provided for it in said immediately
preceding sentence without first giving Tenant notice of such default and the
opportunity to cure the same within the time provided in said clause (1) and/or
clause (2), as the case may be.  Tenant hereby expressly waives any and all
rights of redemption granted by or under any present or future laws in the event
of Tenant being evicted or dispossessed for any cause, or in the event Landlord
terminates this lease as provided in this Article.

     (B)  OBLIGATIONS THEREAFTER

     In case of any such termination, Tenant will indemnify Landlord each month
against all loss of Fixed Rent and additional rent and against all obligations
which Landlord may incur by reason of any such termination between the time of
termination and the expiration of the Term; or at the election of Landlord,
exercised at the time of termination or at any time thereafter, Tenant will
indemnify Landlord each month until the exercise of the election against all
loss of Fixed Rent and additional rent and against all obligations which
Landlord may incur by reason of such termination during the period between the
time of the termination and the exercise of the election, and upon the exercise
of the election Tenant will pay to Landlord as damages such amount as at the
time of the exercise of the election represents the amount by which the rental
value of the demised premises for the

                                     -15-
<PAGE>

period from the exercise of the election until the expiration of the Term shall
be less than the amount of rent and other payments provided herein to be paid by
Tenant to Landlord during said period. It is understood and agreed that at the
time of the termination or at any time thereafter Landlord may rent the demised
premises, and for a term which may expire before or after the expiration of the
Term, without releasing Tenant from any liability whatsoever, that Tenant shall
be liable for any expenses incurred by Landlord in connection with obtaining
possession of the demised premises, with removing from the demised premises
property of Tenant and persons claiming under it (including warehouse charges),
with putting the demised premises into good condition for reletting, and with
any reletting, including, but without limitation, reasonable attorneys' fees and
brokers fees, and that any monies collected from any reletting shall be applied
first to the foregoing expenses and then to the payment of Fixed Rent,
additional rent and all other payments due from Tenant to Landlord. Landlord
agrees that it shall use reasonable efforts to mitigate its damages. For
purposes of the foregoing, "reasonable efforts" shall mean only the listing of
the demised premises for lease with at least one (1) broker in the area in which
the demised premises are located.

                                 ARTICLE VIII
                              CASUALTY AND TAKING

8.   (A)  CASUALTY AND TAKING

     In case during the Term all or any substantial part of the demised
premises, the Building, or Lot or any one or more of them, are damaged by fire
or any other casualty or by action of public or other authority or are taken by
eminent domain, this lease shall terminate at Landlord's election, which may be
made notwithstanding Landlord's entire interest may have been divested, by
notice given to Tenant within thirty days after the occurrence of the event
giving rise to the election to terminate.  Said notice shall, in the case of
damage as aforesaid, specify the effective date of termination which shall be
not less than thirty nor more than sixty days after the date of notice of such
termination.  In the case of any such taking by eminent domain, the effective
date of the termination shall be the day on which the taking authority shall
take possession of the taken property.  Fixed Rent and additional rent shall be
apportioned and adjusted as of the effective date of any such termination.  If
in any such case the demised premises are rendered unfit for use and occupation
and this lease is not so terminated, Landlord shall use due diligence to put the
demised premises, or, in the case of a taking, what may remain thereof
(excluding any items which Tenant may be required or permitted to remove from
the demised premises at the expiration of the Term) into proper condition for
use and occupation, but Landlord shall not be required to spend more than the
net proceeds of insurance or award of damages it receives therefor, and a just
proportion of the Fixed Rent and additional rent according to the nature and
extent of the injury to the demised premises shall be abated until the demised
premises or such remainder shall have

                                     -16-
<PAGE>

been put by Landlord in such condition; and in case of a taking which
permanently reduces the area of the demised premises, a just proportion of the
Fixed Rent shall be abated for the remainder of the Term. If there shall be
damage or destruction to the demised premises by fire or other casualty which
shall not be repaired or restored by Landlord within a period of nine (9) months
after the date of such damage or destruction, then Tenant, as Tenant's sole
remedy, may terminate the Term of this lease by a notice to Landlord within
sixty (60) days after the expiration of such nine (9) month period; provided
that said repair or restoration shall not have been completed prior to the
receipt by Landlord of said notice.

     (B)  RESERVATION OF AWARD

     Landlord reserves to itself any and all rights to receive awards made for
damage to the demised premises, Building or Lot and the leasehold hereby
created, or any one or more of them, accruing by reason of any exercise of the
right of eminent domain or by reason of anything done in pursuance of public or
other authority.  Tenant hereby releases and assigns to Landlord all of Tenant's
rights to such awards, and covenants to deliver such further assignments and
assurances thereof as Landlord may from time to time request.  It is agreed and
understood, however, that Landlord does not reserve to itself, and Tenant does
not assign to Landlord, any damages payable for (1) movable equipment installed
by Tenant or anybody claiming under Tenant at its own expense or (ii) relocation
expenses, but in each case only if and to the extent that such damages are
recoverable by Tenant from such authority in a separate action and without
reducing Landlord's award of damages.

                                  ARTICLE IX
                                   MORTGAGEE

9.   (A)  SUBORDINATION TO MORTGAGES

     It is agreed that the rights and interest of Tenant under this lease shall
be: (i) subject and subordinate to the lien of any present or future first
mortgage and to any and all advances to be made thereunder, and to the interest
thereon, upon the demised premises or any property of which the demised premises
are a part, if the holder of such mortgage shall elect, by notice to Tenant, to
subject and subordinate the rights and interest of Tenant under this lease to
the lien of its mortgage; or (ii) prior to the lien of any present or future
first mortgage, if the holder of such mortgage shall elect, by notice to Tenant,
to give the rights and interest of Tenant under this lease priority to the lien
of its mortgage.  It is understood and agreed that the holder of such mortgage
may also elect, by notice to Tenant, to make some provisions hereof subject and
subordinate to the lien of its mortgage while granting other provisions hereof
priority to the lien of its mortgage.  In the event of any of such elections,
and upon notification by the holder of such mortgage to that effect,

                                     -17-
<PAGE>

the rights and interest of Tenant under this lease shall be deemed to be
subordinate to, or to have priority over, as the case may be, the lien of said
mortgage, irrespective of the time of execution or time of recording of any such
mortgage. Tenant agrees that it will, upon request of Landlord, execute,
acknowledge and deliver any and all instruments deemed by Landlord necessary or
desirable to evidence or to give notice of such subordination or priority. The
word "mortgage" as used herein includes mortgages, deeds of trust or other
similar instruments and modifications, consolidations, extensions, renewals,
replacements and substitutes thereof. Whether the lien of any mortgage upon the
demised premises or any property of which the demised premises are a part shall
be superior or subordinate to this lease and the lien hereof, Tenant agrees that
it will, upon request, attorn to the holder of such mortgage or anyone claiming
under such holder and their respective successors and assigns in the event of
foreclosure of or similar action taken under such mortgage. Tenant further
agrees that it shall not subordinate its interest in this lease to the lien of
any junior mortgage, security agreement or lease affecting the demised premises,
unless the holder of the first mortgage upon the demised premises or property
which includes the demised premises shall consent thereto. Notwithstanding
anything to the contrary contained in this Article 9, Tenant shall not be
required to subordinate this lease and the lien hereof to the lien of any
mortgage unless the holder of such mortgage shall enter into an agreement with
Tenant, recordable in form, to the effect that in the event of foreclosure of,
or similar action taken under, such mortgage, Tenant's possession of the demised
premises shall not be terminated or disturbed by such mortgage holder or anyone
claiming under such mortgage holder so long as Tenant shall not be in default
under this lease. Landlord agrees that it shall use its best efforts to obtain
such an agreement from the present mortgagee of the Building. Best efforts shall
not require Landlord to expend any money.

     (B)  LIMITATION ON MORTGAGEE'S LIABILITY

     Upon entry and taking possession of the mortgaged premises for any purpose,
the holder of a mortgage shall have all rights of Landlord, and during the
period of such possession Landlord, not such mortgage holder, shall have the
duty to perform all of Landlord's obligations hereunder.  No such holder shall
be liable, either as a mortgagee or as holder of a collateral assignment of this
lease, to perform, or be liable in damages for failure to perform, any of the
obligations of Landlord unless and until such holder shall succeed to Landlord's
interest herein through foreclosure of its mortgage or the taking of a deed in
lieu of foreclosure, and thereafter such mortgage holder shall not be liable for
the performance of any of Landlord's obligations hereunder, except for the
performance of those obligations which arise during the period of time that such
mortgage holder holds Landlord's right, title and interest in this lease, such
liability to be limited to the same extent as Landlord's liability is limited
pursuant to Section 10(E) hereof.

                                     -18-
<PAGE>

     (C)  NO RELEASE OR TERMINATION

     No act or failure to act on the part of Landlord which would entitle Tenant
under the terms of this lease, or by law, to be relieved of any of Tenant's
obligations hereunder or to terminate this lease, shall result in a release or
termination of such obligations or a termination of this lease unless (i) Tenant
shall have first given written notice of Landlord's act or failure to act to
Landlord's mortgagees of which Tenant has been given notice, if any, specifying
the act or failure to act on the part of Landlord which could or would be the
basis of Tenant's rights and (ii) such mortgagees, after receipt of such notice,
have failed or refused to correct or cure the condition complained of within a
reasonable time thereafter, but nothing contained in this Section (C) shall be
deemed to impose any obligation on any such mortgagee to correct or cure any
such condition.  "Reasonable time" as used above means and includes a reasonable
time to obtain possession of the mortgaged premises, if the mortgagee elects to
do so, and a reasonable time to correct or cure the condition.  Finally, Tenant
agrees that so long as any present or future mortgage shall remain in effect
Tenant shall not alter, modify, amend, change, surrender or cancel this lease
nor pay the rent due hereunder in advance for more than thirty (30) days, except
as may be required herein, without the prior written consent of the holder
thereof, and Tenant will not seek to be made an adverse or defendant party in
any action or proceeding brought to enforce or foreclose such mortgage.

                                   ARTICLE X
                              GENERAL PROVISIONS

10.  (A)  CAPTIONS

     The captions of the Articles are for convenience and are not to be
considered in construing this lease.

     (B)  SHORT FORM LEASE

     Upon request of either party both parties shall execute and deliver a short
form of this lease in form appropriate for recording, and if this lease is
terminated before the Term expires, an instrument in such form acknowledging the
date of termination.  No such short form lease shall contain any indication of
the amount of the rentals payable hereunder by Tenant.

     (C)  RELOCATION

     Intentionally Omitted.

                                     -19-
<PAGE>

     (D)  NOTICES

     All notices and other communications authorized or required hereunder shall
be in writing and shall be given by mailing the same by certified or registered
mail, return receipt requested, postage prepaid, by mailing the same by Express
Mail or by having the same delivered by a commercial delivery service such as
Federal Express, UPS, Purolator Courier and the like.  If given to Tenant the
same shall be directed to Tenant at Tenant's Address or to such other person or
at such other address as Tenant may hereafter designate by notice to Landlord;
and if given to Landlord the same shall be directed to Landlord at Landlord's
Address, or to such other person or at such other address as Landlord may
hereafter designate by notice to Tenant.  In the event the notice directed as
above provided shall not be received upon attempted delivery thereof to the
proper address and shall be returned by the Postal Service or delivery service
to the sender because of a refusal of receipt, the absence of a person to
receive, or otherwise, the time of the giving of such notice shall be the first
business day on which delivery was so attempted.

     After receiving notice from Landlord or from any person, firm or other
entity that such person, firm or other entity holds a mortgage which includes
the demised premises as part of the mortgaged premises, no notice from Tenant to
Landlord shall be effective unless and until a copy of the same is given by
certified or registered mail to such holder, and the curing of any of Landlord's
defaults by such holder shall be treated as performance by Landlord, it being
understood and agreed that such holder shall be afforded a reasonable period of
time after the receipt of such notice in which to effect such cure.

     (E)  SUCCESSORS AND ASSIGNS

     The obligations of this lease shall run with the land, and this lease shall
be binding upon and inure to the benefit of the parties hereto and their
respective heirs, legal representatives, successors and assigns, except that the
Landlord named herein and each successive owner of Landlord's interest in this
lease shall be liable only for the obligations of Landlord accruing during the
period of its ownership.  Whenever Landlord's interest in this lease is owned by
a trustee or trustees, the obligations of Landlord shall be binding upon
Landlord's trust estate, but not upon any trustee, beneficiary or shareholder of
the trust individually.  Without limiting the generality of the foregoing, and
whether or not Landlord's interest in this lease is owned by a trustee or
trustees, Tenant specifically agrees to look solely to Landlord's interest in
the Building and Lot for recovery of any judgment from Landlord, it being
specifically agreed that neither Landlord, any trustee, beneficiary or
shareholder of any trust estate for which Landlord acts nor any person or entity
claiming by, through or under Landlord shall ever otherwise be personally liable
for any such judgment.

                                     -20-
<PAGE>

     (F)  NO SURRENDER

     The delivery of keys to any employee of Landlord or to Landlord's agent or
any employee thereof shall not operate as a termination of this lease or a
surrender of the demised premises.

     (G)  WAIVERS AND REMEDIES

     The failure of Landlord or of Tenant to seek redress for violation of, or
to insist upon the strict performance of any covenant or condition of this
lease, or, with respect to such failure of Landlord, any of the rules and
regulations referred to in Section 6(4), whether heretofore or hereafter adopted
by Landlord, shall not be deemed a waiver of such violation nor prevent a
subsequent act, which would have originally constituted a violation, from having
all the force and effect of an original violation, nor shall the failure of
Landlord to enforce any of said rules and regulations against any other tenant
in the Building be deemed a waiver of any such rules or regulations as far as
Tenant is concerned.  Landlord agrees it shall not discriminate against Tenant
in enforcing said rules or regulations.  The receipt by Landlord of Fixed Rent
or additional rent with knowledge of the breach of any covenant of this lease
shall not be deemed a waiver of such breach by Landlord unless such waiver be in
writing signed by Landlord.  No consent or waiver express or implied, by
Landlord or Tenant to or of any breach of any agreement or duty shall be
construed as a waiver or consent to or of any other breach of the same or any
other agreement or duty.  No acceptance by Landlord of a lesser sum than the
Fixed Rent and additional rent then due shall be deemed to be other than on
account of the earliest installment of such rent due, nor shall any endorsement
or statement on any check or any letter accompanying any check or payment as
rent be deemed as accord and satisfaction, and Landlord may accept such check or
payment without prejudice to Landlord's right to recover the balance of such
installment or pursue any other remedy available to it.  The specific remedies
to which Landlord may resort under the terms of this lease are cumulative and
are not intended to be exclusive of any other remedies or means of redress to
which it may be lawfully entitled in case of any breach or threatened breach by
Tenant of any provisions of this lease.  In addition to the other remedies
provided in this lease, Landlord shall be entitled to the restraint by
injunction of the violation or attempted or threatened violation of any of the
covenants, conditions or provisions of this lease or to a decree compelling
specific performance of any such covenants, conditions or provisions.  If any
term of this lease, or the application thereof to any person or circumstances
shall be held, to any extent, to be invalid or unenforceable, the remainder of
this lease, or the application of such term to persons or circumstances other
than those as to which it has been held invalid or unenforceable, shall not be
affected thereby, and each term of this lease shall be valid and enforceable to
the fullest extent permitted by law.  If any interest to be paid by Tenant
hereunder shall exceed the highest lawful rate which

                                     -21-
<PAGE>

Landlord may recover from Tenant, such interest shall be reduced to such highest
lawful rate of interest.

     (H)  SELF-HELP

     If Tenant shall at any time default in the performance of any obligation
under this lease, Landlord shall have the right, but shall not be obligated, to
enter upon the demised premises and to perform such obligation, notwithstanding
the fact that no specific provision for such performance by Landlord is made in
this lease with respect to such default.  In performing such obligation,
Landlord may make any payment of money or perform any other act.  All sums so
paid by Landlord (together with interest, from the time paid by Landlord until
the time Tenant repays the same to Landlord, at the Lease Interest Rate), shall
be deemed to be additional rent and shall be payable to Landlord immediately on
demand.  Landlord may exercise the foregoing right without waiving any other of
its rights or releasing Tenant from any of its obligations under this lease.

     (I)  ESTOPPEL CERTIFICATE

     Tenant and Landlord agree from time to time after the Commencement Date,
upon not less than five days' prior written request by either party, to execute,
acknowledge and deliver to the other a statement in writing certifying that this
lease is unmodified and in full force and effect; that Landlord and Tenant have
completed their required work; that Tenant has no defenses, offsets or
counterclaims against its obligations to pay the Fixed Rent and additional rent
and to perform its other covenants under this lease; that there are no uncured
defaults of Landlord or Tenant under this lease (or, if there have been any
modifications, that this lease is in full force and effect as modified and
stating the modifications, and, if there are any defenses, offsets,
counterclaims, or defaults, setting them forth in reasonable detail); and the
dates to which the Fixed Rent, additional rent and other charges have been paid.
Any such statement delivered pursuant to this Section (I) may be relied upon by
any prospective purchaser or mortgagee of premises which include the demised
premises or any prospective assignee of any such mortgagee.

     (J)  WAIVER OF SUBROGATION

     (1)  Tenant hereby releases Landlord to the extent of Tenant's insurance
coverage, from any and all liability for any loss or damage caused by fire or
any of the extended coverage casualties or any other casualty insured against,
even if such fire or other casualty shall be brought about by the fault or
negligence of Landlord or its agents, provided, however this release shall be in
force and effect only with respect to loss or damage occurring during such time
as Tenant's policies covering such loss or damage shall contain a clause to the
effect that this release shall not affect said policies or the right of Tenant
to recover thereunder.  Tenant agrees that

                                     -22-
<PAGE>

its fire and other casualty insurance policies will include such a clause so
long as the same is includable without extra cost, or if extra cost is
chargeable therefor, so long as Landlord pays such extra cost. If extra cost is
chargeable therefor, Tenant will advise Landlord thereof and of the amount
thereof. Landlord at its election, may pay the same, but shall not be obligated
to do so.

     (2)  Landlord hereby releases Tenant, to the extent of the Landlord's
insurance coverage, from any and all liability for any loss or damage caused by
fire or any of the extended coverage casualties or any other casualty insured
against, even if such fire or other casualty shall be brought about by the fault
or negligence of Tenant or its agents, provided, however, this release shall be
in force and effect only with respect to loss or damage occurring during such
time as Landlord's policies covering such loss or damage shall contain a clause
to the effect that this release shall not affect said policies or the right of
Landlord to recover thereunder.  Landlord agrees that its fire and other
casualty insurance policies will include such a clause so long as the same is
includable without extra cost, or if extra cost is chargeable therefor, so long
as Tenant pays such extra cost.  If extra cost is chargeable therefor, Landlord
will advise Tenant thereof and of the amount thereof.  Tenant at its election
may pay the same, but shall not be obligated to do so.

     (K)  BROKERS

     Tenant and Landlord hereby represent and warrant to the other that other
than Lynch, Murphy, Walsh & Partners and Boston Real Estate Partners ("the
Brokers") they have dealt with no other broker in connection with this lease and
there are no other brokerage commissions or other finders' fees payable in
connection herewith. Tenant hereby agrees to hold Landlord harmless from, and
indemnified against, all loss or damage (including without limitation, the cost
of defending the same) arising from any claim by any broker claiming to have
dealt with Tenant.  Landlord hereby agrees to hold Tenant harmless from, and
indemnified, against all loss or damage (including without limitation, the cost
of defending the same) arising from any claim by any broker claiming to have
dealt with Landlord.  Landlord shall pay the commission due the Brokers by
separate agreement.

     (L)  LANDLORD'S DEFAULTS

     Landlord shall not be deemed to have committed a breach of any obligation
to make repairs or alterations or perform any other act unless: (1) it shall
have made such repairs or alterations or performed such other act negligently;
or (2) it shall have received notice from Tenant designating the particular
repairs or alterations needed or the other act of which there has been failure
of performance and shall have failed to make such repairs or alterations or
performed such other act within a reasonable time after the receipt of such
notice; and in the latter event Landlord's liability shall

                                     -23-
<PAGE>

be limited to the cost of making such repairs or alterations or performing such
other act.

     (M)  EFFECTIVENESS OF LEASE

     The submission of this lease for examination does not constitute a
reservation of, or option for, the demised premises, and this lease becomes
effective as a lease only upon execution and unconditional delivery thereof by
both Landlord and Tenant.

     (N)  HAZARDOUS MATERIALS

     Tenant shall not (either with or without negligence) cause or permit the
escape, disposal or release of any biologically or chemically active or other
hazardous substances, or materials.  Tenant shall not allow the storage or use
of such substances or materials in any manner not sanctioned by law or by the
highest standards prevailing in the industry for the storage and use of such
substances or materials, nor allow to be brought into the Lot any such materials
or substances except to use in the ordinary course of Tenant's business, and
then only after written notice is given to Landlord of the identity of such
substances or materials.  Without limitation, hazardous substances and materials
shall include those described in the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended, 42 U.S.C.  Section 9601 et
seq., the Resource Conservation and Recovery Act, as amended, 42 U.S.C Section
6901 et seq., any applicable state or local laws and the regulations adopted
under these acts.  If any lender or governmental agency shall ever require
testing to ascertain whether or not there has been any release of hazardous
materials then the reasonable costs thereof shall be reimbursed by Tenant to
Landlord upon demand as additional rent if Tenant caused such release, or if
Landlord has a reasonable basis to believe that Tenant caused a release of
hazardous materials.  In addition, Tenant shall execute affidavits,
representations and the like from time to time at Landlords' request concerning
Tenant's best knowledge and belief regarding the presence of hazardous
substances or materials on the demised premises.  In all events, Tenant shall
indemnify Landlord in the manner elsewhere provided in this lease from any
release of hazardous materials on the demised premises occurring while Tenant is
in possession, or elsewhere if caused by Tenant or persons acting under Tenant.
The within covenants shall survive the expiration or earlier termination of the
term of this lease.  Landlord agrees that it shall indemnify, defend and hold
Tenant harmless from and against any claims, suits, causes of action, costs and
fees, including attorneys' fees, arising from or connected with any
contamination, claim of contamination, loss or damage, including without
limitation the cost of treating in order to confirm the presence, containment
and/or removal of such oil, materials or waste brought onto the Lot or into the
Building prior to the date of this lease.

                                     -24-
<PAGE>

                                  ARTICLE XI
                               SECURITY DEPOSIT

     11.  Simultaneously with the execution of this lease, Tenant shall deliver
to Landlord as security for the payment of the rents and the performance and
observance of the agreements and conditions in this lease combined on the part
of Tenant to be performed and observed, an irrevocable letter of credit from a
bank approved by Landlord, such letter of credit to initially be in the amount
of $92,000.00, and to expire not earlier than the thirtieth (30th) day after the
expiration of the Term of this lease. Said letter of credit shall expressly
state that it is assignable by landlord to any subsequent holder of the
landlord's interest in this lease (including, without limitation, the holder of
any mortgage upon the Shopping Center). Said letter of credit shall provide that
Landlord may draw against the same upon the presentation to the bank of
Landlord's draft and a certification on behalf of Landlord that Tenant is in
default in the payment of any rents and/or the performance and observance of any
of the agreements and conditions in this lease contained on the part of Tenant
to be performed and observed. There shall be no other conditions whatsoever to
Landlord's right to draw against said letter of credit. Landlord agrees that
provided Tenant is not in default beyond any applicable cure period in the
payment of rents and the performance and observance of the agreements and
conditions in this lease contained on the part of Tenant to be performed and
observed, said letter of credit may be replaced, commencing on the thirteenth
(13th) month of the Term by a letter of credit in the amount of Sixty Nine
Thousand Dollars ($69,000.00); and provided Tenant is not in default, as
aforesaid, beyond any applicable cure period, said replacement letter of credit
may also be replaced, commencing with the twenty fifth (25th) month of the Term,
by a letter of credit in the amount of Forty-Six Thousand Dollars ($46,000.00).
Each replacement letter of credit shall be in the form of the original letter of
credit. It is understood and agreed that Landlord shall always have the right to
draw down on said letter of credit, or any part thereof, as aforesaid in the
event of any such default or defaults, without prejudice to any other remedy or
remedies which Landlord may have, or Landlord may pursue any other such remedy
or remedies in lieu of drawing down on the letter of credit. If Landlord shall
draw down on said letter of credit or any part thereof as aforesaid, Tenant
shall upon demand replace the letter of credit with a letter of credit in the
original amount.

                                  ARTICLE XII
                                 MODIFICATION


     12.  In the event that any holder or prospective holder of any mortgage
which includes the demised premises as part of the mortgaged premises, shall
request any modification of any of the provisions of this lease, other than a
provision which unreasonably modifies Tenant's rights hereunder or which are
directly related to the rents or other charges payable hereunder, the duration
of the Term hereof, or

                                     -25-
<PAGE>

the size, use or location of the demised premises, Tenant agrees that Tenant
will enter into an amendment of this lease containing each such modification so
requested.

     EXECUTED as a sealed instrument in two or more counterparts as of the day
and year first above written.

                              LANDLORD:
                              BerCar II LLC, BY ITS MANAGERS:

                              ALTID ENTERPRISES LIMITED
                              PARTNERSHIP

                              By  /s/ Raymond A. Carye
                                  ----------------------------
                                  Raymond A. Carye, General
                                  Partner


                              By  /s/ Barbara F. Carye
                                  ----------------------------
                                  Barbara F. Carye, General
                                  Partner



                              BERKELEY INVESTMENTS, INC.


                              By  /s/ Young K. Park
                                  ----------------------------
                                  Young K. Park, President



                              TENANT:
                              SYCAMORE NETWORKS, INC.


                              By  /s/ Daniel Smith
                                  ----------------------------

                              ATTEST:

                              By  /s/ John Dowling
                                  ----------------------------
                              (Corporate Seal)

                                     -26-
<PAGE>

                                   EXHIBIT A

                                     PLAN
<PAGE>

                                   EXHIBIT B

                             INTENTIONALLY OMITTED
<PAGE>

                                   EXHIBIT C

                             INTENTIONALLY OMITTED
<PAGE>

                                   EXHIBIT D

                              LANDLORD'S SERVICES


     Landlord shall cause the paved portions of the Lot and sidewalks to be kept
reasonably free and clear of snow, ice and refuse and shall cause the landscaped
areas (if any) of the Lot to be maintained in a reasonably attractive
appearance.
<PAGE>

                                   EXHIBIT E

                             RULES AND REGULATIONS

     1.   The sidewalks, paved and/or landscaped areas shall not be obstructed
or encumbered by Tenant or used for any purpose other than ingress and egress to
and from the demised premises.

     2.   No sign, advertisement, notice or other lettering shall be exhibited,
inscribed, painted or affixed by Tenant on any part of the demised premises or
Building so as to be visible from outside the demised premises without the prior
written consent of Landlord.  All such signs shall comply with the sign criteria
set forth in Exhibit G attached to this lease and made a part hereof.  In the
event of the violation of this paragraph, Landlord may remove same without any
liability, and may charge the expense incurred in such removal to Tenant, as
additional rent.

     3.   No awnings, curtains, blinds, shades, screens or other projections
shall be attached to or hung in, or used in connection with, any window of the
demised premises or any outside wall of the Building without the prior written
consent of Landlord.  Such awnings, curtains, blinds, shades, screens or other
projections must be of a quality, type, design and color, and attached in the
manner, approved by Landlord.  If any portion of the demised premises which is
not used for office purposes shall have windows, such windows shall be equipped
with curtains, blinds or shades approved by Landlord, and said curtains, blinds
or shades shall be kept closed at all times.

     4.   The water and wash closets and other plumbing fixtures shall not be
used for any purposes other than those for which they were designed and
constructed, and no sweepings, rubbish, rags, acids, chemicals, process water,
cooling water or like substances shall be deposited therein.  Said plumbing
fixtures and the plumbing system of the Building shall be used only for the
discharge of so-called sanitary waste.  All damage resulting from any misuse of
said fixtures and/or plumbing system by Tenant or anyone claiming under Tenant
shall be borne by Tenant.

     5.   Tenant must, upon the termination of its tenancy, return to Landlord
all locks, cylinders and keys to the demised premises and any offices therein.

     6.   Tenant shall keep any sidewalks and planters in front of the demised
premises reasonably free and clear of litter and refuse regardless of the source
thereof, in the event that litter and/or refuse shall be deposited thereon
between the times of Landlord's regularly scheduled maintenance of said
sidewalks and planters.

     7.   Tenant shall, at Tenant's expense, provide artificial light and
electric current for the employees of Landlord and/or Landlord's contractors
while making repairs or alterations in the demised premises.
<PAGE>

     8.   Tenant shall not make, or permit to be made, any unseemly or
disturbing odors or noises or disturb or interfere with occupants of the
Building or those having business with them, whether by use of any musical
instrument, radio, machine, or in any other way.

     9.   Canvassing, soliciting, and peddling in the Building are prohibited
and Tenant shall cooperate to prevent the same.

     10.  Tenant shall keep the demised premises free at all times of pests,
rodents and other vermin, and Tenant shall keep all trash and rubbish stored in
containers of a type approved by Landlord, such containers to be kept at
locations designated by Landlord.  Tenant shall cause such containers to be
emptied whenever necessary to prevent them from overflowing or from producing
any objectionable odors.

     11.  Landlord reserves the right to rescind, alter, waive and/or establish
any rules and regulation, which, in its judgment, are necessary, desirable or
proper for its best interests and the best interests of the occupants of the
Building.

     12.  The access roads, driveways, entrances and exits shall not be
obstructed or encumbered by Tenant or used for any purpose other than ingress
and egress.
<PAGE>

                                   EXHIBIT F

                           LEGAL DESCRIPTION OF LOT


     Beginning at an iron rod at the northeasterly corner of the herein
described premises, which point is the southeasterly corner of the land
described in a deed given by Orion L.  Woodbury et al to New England Power
Company, dated May 28, 1954, and recorded with Middlesex North District Deeds,
Book 1257, Page 510; thence running south 78 degrees 30 feet west by land of
said New England Power Company, sixteen hundred ninety-seven and 72/100
(1,697.72) feet to a stone bound; July 29, 1999 thence running south 80 degrees
15 feet west by said New England Power Company land, four hundred ninety-seven
and 1/10 (497.1) feet to a pipe at land now or formerly of Edward B.  Russell;
thence running southerly by said Russell land, five hundred forty-six and 6/10
(546.6) feet to a stone bound at land now or formerly of Frank A. P. Coburn;
thence running easterly along said Coburn land to a stake and stones; thence
running south 15 degrees east, two hundred forty-seven and 5/10 (247.5) feet to
a stone bound; thence running south 65 1/2 degrees east, ninety and 75/100
(90.75) feet to a stone bound; thence running north 60 degrees east, seventeen
hundred thirty-two and 5/10 (1,732.5) feet to said Mill Road; thence running
northerly along said Road to the point of beginning.
<PAGE>

                                   EXHIBIT G

                                 SIGN CRITERIA