1/29/98
                              Loan Agreement
                                                                  
        

                             January 29, 1998

                                  Between



BORROWER

OPTEK TECHNOLOGY, INC.
1215 West Crosby Road
Carrollton, Texas 75006
BANK

NATIONSBANK OF TEXAS, N.A.
901 Main Street, 7th Floor
Dallas, Texas 75202




             In consideration of the creation of the revolving
facility described below and the mutual
covenants and agreements contained herein, and intending to be
legally bound hereby, Bank and
Borrower agree as follows:

             1.0          Certain Definitions.  The terms
"Floating Base Rate", "LIBO Rate", "LIBO Business
Day" and "LIBO Interest Period" are defined in the Note referred
to below.  In addition, the
following terms shall have the meaning set forth with respect
thereto:

                          "Adjusted Current Liabilities": see
Section 5.2.

                          "Agreement" means this Loan Agreement
and all subsequent modifications and
             amendments hereto.

                          "Commitment" means the obligation of
Bank, subject to the terms and conditions of
             this Agreement, to make Loans which shall not exceed
at any one time outstanding
             $10,000,000.

                          "Contested in Good Faith" means, as to
any payment, tax, assessment, charge, levy,
             lien, encumbrance or claim, contesting the amount,
applicability or validity thereof in good
             faith by appropriate proceedings or other
appropriate actions promptly initiated and diligently
             conducted in a manner satisfactory to Bank, provided
(a) adequate reserves satisfactory to
             Bank have been established, and (b) the enforcement
of the contested payment, tax,
             assessment, charge, levy, lien, encumbrance or claim
is stayed in a manner satisfactory to
             Bank pending the resolution of such contest.

                          "EBITDA": see Section 5.1.

                          "ERISA" means the Employee Retirement
Income Security Act of 1974, as amended,
             and the regulations promulgated thereunder, as in
effect as  of the date hereof and any
             subsequent provisions which are amendatory thereof,
supplemental thereto or substituted
             therefor.  In addition, the terms "Commonly
Controlled Entity," "Multiemployer Plan,"
             "PBGC," "Plan," "Prohibited Transaction," and
"Reportable Event" have the same means as
             provided therefor in ERISA.
<PAGE>
                          "GAAP" means generally accepted
accounting principles as in effect from time to
             time, applied on a basis consistent (except for
changes approved by Borrower s independent
             public accountant) with the most recent financial
statements of Borrower delivered to Bank.

                          "Guarantor" means each subsidiary
executing a Guaranty Agreement. 

                          "Guaranty Agreement": see Section 2.4.

                          "Hazardous Materials" include all
materials defined as hazardous materials or
             substances under any local, state or federal
environmental laws, rules or regulations, and
             petroleum, petroleum products, oil and asbestos.

                          "Loan Documents" means this Agreement,
the Note, the Negative Pledge Agreement,
             the Guaranty Agreements, the Officer's Certificates,
the Section 26.02 Notice, and all other
             documents, instruments, guarantees, security
agreements, deeds of trust, pledge agreements,
             certificates and agreements executed and/or
delivered by Borrower, or any guarantor or third
             party in connection with any Loan.

                          "Loans": see Section 2.0.

                          "Material Adverse Effect" means a set
of circumstances or events any one of which
             (i) has or could have a material and adverse effect
upon the validity or enforceability of or
             would result in a Potential Default under any of the
Loan Documents, (ii) is material and
             adverse to the business, operations, affairs,
financial condition, assets or properties of
             Borrower or any Guarantor, (iii) could materially
and adversely impair the ability of
             Borrower or any Guarantor to fulfill its obligations
under the Loan Documents, or (iv) could
             materially and adversely impair the value of any
collateral or the ability of the secured party
             to realize thereon.

                          "Maturity Date" means January 15, 2001.

                          "Mexican Subsidiaries" mean Optron De
Mexico, S.A. de C.V., and Semicondores
             Opticos, S.A. de C.V.

                          "Negative Pledge Agreement": see
Section 2.3

                          "Net Depreciation": see Section 5.1.

                          "Net Income": see Section 5.1.

                          "No Cure Period Covenants" mean any
term, covenant or agreement set forth in
             Sections 5.1 through 5.4, Sections 6.1 and 6.2,
Sections 7.1 through 7.12, Section 9.1,
             Section 9.2, Section 12.0 and Section 13.9 hereof.

                          "Note" means that certain promissory
note made by Borrower payable to the order of
             Bank in the original principal sum of $10,000,000
dated January 29, 1998, and all renewals,
             extensions, modifications and amendments thereto,
and substitutions therefor.
<PAGE>
                          "Obligations" means the obligations of
Borrower:

                          (a)           to pay all indebtedness
arising out of this Agreement, any future
                          advances under this Agreement, and all
renewals, extensions or amendments of such
                          indebtedness or any part thereof or any
such future advances; 

                          (b)           to pay the principal of
and interest on the Note in accordance with the
                          terms thereof, and all renewals,
extensions, modifications and amendments of such
                          Note or any part thereof, and any
future advances made pursuant thereto; 

                          (c)           to repay to Bank all
amounts advanced by Bank hereunder or under
                          the other Loan Documents on behalf of
Borrower, including, without limitation,
                          advances for principal or interest
payments to prior secured parties, mortgagees, or
                          lienors, or for taxes, levies,
insurance, rent, repairs to or maintenance or storage of
                          any of the collateral; 

                          (d)           to pay any and all other
indebtedness of Borrower to Bank of every
                          kind, nature and description, direct or
indirect, primary or secondary, secured or
                          unsecured (including overdrafts), joint
or several, absolute or contingent, due or to
                          become due, now existing or hereafter
arising, regardless of how it may be evidenced,
                          including without limitation all future
advances, whether or not presently contemplated
                          by the parties hereto;

                          (e)           to perform fully all of
the terms and provisions of each of the
                          instruments constituting the Loan
Documents; and 

                          (f)           to reimburse Bank, on
demand, for all of Bank's expenses and costs,
                          which Borrower and Guarantors are
obligated to pay pursuant to the terms of the
                          Loan Documents.

                          "Permitted Liens" mean (i) liens for
current taxes not delinquent or for taxes being
             Contested in Good Faith, (ii) liens arising in the
ordinary course of business for sums being
             Contested in Good Faith, or for sums not due, and in
either case not involving any deposits
             or advances for borrowed money or the deferred
purchase of property or services, (iii) liens
             incurred in the ordinary course of business for
amounts not yet due and payable in connection
             with worker s compensation, unemployment insurance
or other forms of governmental
             insurance or benefits, (iv) mechanic s, worker s,
materialmen s and other like liens arising in
             the ordinary course of business in respect of
obligations which are not delinquent or which are
             being Contested in Good Faith, (v) liens and
security interests, if any, in favor of Bank,
             (vi) purchase-money liens and security interests on
any property acquired after the date of this
             Agreement securing Purchase Money Debt up to
$500,000 in the aggregate at any time
             outstanding, (vii) liens securing lease expenditures
permitted by Section 7.2 hereof, and
             (viii) minor defects and irregularities which
neither (1) are liens or security interests which
             secure other indebtedness or obligations, nor (2)
materially impair the value of such asset or
             the use thereof for the purposes for which such
asset is held.

                          "Plan" means, at any time, any employee
benefit plan which is covered by ERISA
             and in respect of which Borrower or any Commonly
Controlled Entity is (or, if such plan
             were terminated at such time, would under ERISA be
deemed to be) an "employer" as defined
             in ERISA.
<PAGE>
                          "Potential Default" means any
condition, event or act, which with the giving of
             notice of the lapse of time, or both, will
constitute an Event of Default hereunder.

                          "Principal Debt": see Section 2.2.

                          "Quick Assets": see Section 5.2.

                          "Section 26.02 Notice": see Section
4.6.

                          "subsidiary" means, with respect to
Borrower, any corporation, limited liability
             company, partnership, limited partnership,
association or other entity the accounts of which
             would be consolidated with those of Borrower if such
financial statements were prepared with
             accordance with GAAP, including without limitation,
the Mexican Subsidiaries.

                          "Tangible Net Worth": see Section 5.3.

                          "Total Funded Debt": see Section 5.1.

             2.0          Loans.  Bank agrees, subject to the
terms and conditions hereof, to lend Borrower at
any time and from time to time on or before the Maturity Date
sums (each year-end called a "Loan"
and collectively the "Loans") which may be repaid and reborrowed
pursuant to the terms hereof and
which shall not exceed at any one time outstanding the amount of
the Commitment.  Whenever
Borrower desires a Loan hereunder, Borrower shall give Bank
notice in the form of Exhibit "A"
attached hereto (a "Borrowing and Interest Notice Request")
specifying (a) the date (which shall be a
Business Day in the case of a Loan based upon the Floating Base
Rate or a LIBO Business Day in the
case of a Loan based upon the LIBO Rate) of the proposed
borrowing, (b) the amount to be
borrowed, (c) the portion of the borrowing constituting a Loan
based upon the Floating Base Rate
and/or a Loan based upon the LIBO Rate (which LIBO Rate based
Loan may only be in integral
multiples of $500,000), and (d) if any portion of the proposed
borrowing constitutes a LIBO Rate
based Loan, the initial LIBO Interest Period selected by Borrower
(thirty days, sixty days or ninety
days).  Such notice shall be given by 10 a.m. (Dallas, Texas
time) on the date of the proposed
borrowing in the case of a Floating Base Rate Loan, and by 10
a.m. (Dallas, Texas time) two (2)
Business Days prior to the date of the proposed borrowing in the
case of a LIBO Rate based Loan. 
The notice required may be given telephonically by Borrower to
Bank, but upon giving such
telephonic notice Borrower shall immediately thereafter provide
Bank with the written notice attached
hereto as Exhibit A.  All notices given under this Section shall
be irrevocable.  Not later than 12
noon (Dallas, Texas time) on the date of the proposed borrowing
and upon fulfillment of all other
conditions required by this Agreement, Bank will make such Loan
available to Borrower by crediting
the amount thereof to Borrower's account with Bank or otherwise
disbursing it as Borrower shall
request in writing.  No Loans may be obtained after the Maturity
Date.

                          2.1           Use of Proceeds.  The
proceeds of Loans may be used solely for general
             corporate purposes.
<PAGE>
                          2.2           Promissory Note.  The
obligation of Borrower to repay the aggregate
             principal balance of all Loans hereunder outstanding
at any one time (the "Principal Debt")
             shall be evidenced by the Note which (a) shall be
payable as to principal on or before the
             Maturity Date for the amount of $10,000,000, or the
Principal Debt then outstanding,
             whichever is less, (b) shall bear interest and be
payable as to interest in the manner therein
             provided, (c) be entitled to the benefits of this
Agreement in the security provided for herein,
             and (d) be in such form as is acceptable to Bank.

                          2.3           Negative, Negative
Pledge.  The Obligations shall be unsecured.  However,
             except for liens expressly permitted by Section 7.5
hereof, until full payment and performance
             of all Obligations of Borrower under the Loan
Documents, all assets of Borrower shall be
             maintained by Borrower free and clear of all liens,
encumbrances, pledges or commitments to
             pledge or not to pledge Borrower s assets to another
creditor.  This obligation shall be further
             evidenced by an agreement (the "Negative Pledge
Agreement"), which shall be in form and
             substance satisfactory to Bank.

                          2.4           Guaranties.  If the
combined Tangible Net Worth of all subsidiaries exceeds
             25% of the Tangible Net Worth of Borrower, then the
payment and performance of the Note
             and all of the other Obligations hereunder and under
the Loan Documents shall be
             unconditionally guaranteed by all subsidiaries then
in existence and thereafter formed or
             acquired pursuant to the terms of one or more
guaranty agreements (each a "Guaranty
             Agreement"), which shall be in form and substance
satisfactory to Bank.  Borrower shall pay
             the reasonable fees and expenses of counsel for Bank
incurred in connection with the
             preparation of the Guaranty Agreements.

                          2.5           Unused Commitment Fee. 
Borrower agrees to pay Bank an unused
             commitment fee for the period commencing with the
date of this Agreement to the Maturity
             Date, computed at the rate of 3/8's of one percent
(0.375%) per annum on the average daily
             unused portion of the Commitment.  The phrase
"unused portion of the Commitment" as used
             in the preceding sentence means the difference
between (a)  $10,000,000, and (b) the
             Principal Debt.  The unused commitment fee shall be
payable quarterly in arrears
             commencing with the calendar quarter ending March
31, 1998.  Borrower authorizes Bank to
             effect payment of the unused commitment fee by
debiting Borrower s account specified in
             Section 5 of the Note for automatic payment.  This
authorization shall not affect the obligation
             of Borrower to pay such sum when due, without
notice, if there are insufficient funds in such
             account to make such payment in full on the due date
thereof, or if Bank fails to debit the
             account.

             3.0          Conditions Precedent to Closing.  The
obligations of Bank as set forth herein are
subject to the satisfaction, unless waived in writing by Bank, of
each of the following conditions:

                          3.1           Loan Origination Fee. 
Borrower shall have paid Bank a loan origination fee
             of $30,000.

                          3.2           Effectiveness of Loan
Documents.  Each of the Loan Documents shall be in
             full force and effect.
<PAGE>
                          3.3           Termination of First
Source Financial Credit Facility.  Borrower shall
             provide documentation satisfactory to Bank
evidencing the termination of lending relationships
             with First Source Financial, Inc., and all other
lenders in existence immediately prior to the
             date hereof, excluding lease arrangements by
Borrower and its subsidiaries previously
             disclosed to Bank in writing.

                          3.4           Credit Opinion.  There
shall have been delivered a favorable credit opinion
             of counsel for Borrower covering organization,
authority, enforceability and such other
             matters incident to the Loan as Bank may reasonably
request.

                          3.5           Insurance Certificate. 
Bank shall have received evidence that Borrower has
             obtained the policies of insurance specified and
required by Section 6.6 hereof.

                          3.6           Documentation and
Proceedings.  Borrower shall have delivered resolutions
             of its boards of directors authorizing its
execution, delivery and performance of the Loan
             Documents to which they are parties.

                          3.7           Section 26.02 Notice. 
Borrower shall have executed a notice in compliance
             with the provisions of Section 26.02 of the Texas
Business and Commerce Code (the "Section
             26.02 Notice").

                          3.8           Representations and
Warranties.  All representations and warranties
             contained herein or in the documents referred to
herein or otherwise made in writing in
             connection herewith or therewith shall be true and
correct with the same force and effect as
             though such representations and warranties have been
made on and as of this date.

             4.0          Conditions Precedent to All Loans.  The
obligation of Bank to make all Loans to
Borrower is subject, at the time of the funding of each such Loan
(the "Funding Date"), to the
satisfaction, unless waived in writing by Bank, of each of the
following conditions:

                          4.1           Borrowing and Interest
Notice Request.  Borrower shall have delivered to
             Bank, within the time frame specified in Section 2.0
hereof, a Borrowing and Interest Notice
             Request appropriately completed in compliance
herewith.

                          4.2           Availability of
Commitment.  The then Principal Debt plus the amount of
             the requested Loan shall be equal to or less than
the Commitment.

                          4.3           Expenses.  Borrower shall
have paid all reasonable expenses of Bank in
             connection with the making of the Loan (other than
those specified in the first sentence of
             Section 12.0 hereof).

                          4.4           Representations and
Warranties.  All representations and warranties
             contained herein shall be true and correct in all
material respects as though such
             representations and warranties have been made on and
as of the Funding Date (except to the
             extent that such representations and warranties
relate solely to an earlier date).

                          4.5           No Default.  There shall
exist no Event of Default or Potential Default 
             hereunder.

                          4.6           Change in Condition.  No
change in the condition (financial or otherwise) of
             Borrower or Guarantors or any other event shall have
occurred which has had or is likely to
             have a Material Adverse Effect.

                          4.7           (a)0         Financial
Covenants.
<PAGE>
                          4.8           Leverage Ratio.  Borrower
will not permit its ratio of Total Funded Debt as
             of the last day of each fiscal quarter to EBITDA for
the period of four consecutive fiscal
             quarters ending on such day, to be greater than 2.0
to 1.0.  "Total Funded Debt" means, as
             of any date of determination, without duplication,
the aggregate principal amount of all
             indebtedness of Borrower and its subsidiaries
outstanding as of such date determined on a
             consolidated basis in accordance with GAAP. 
"EBITDA" means, for any period, Net Income
             for such period, plus, without duplication and to
the extent deducted from revenues in
             determining Net Income, the sum of (a) the aggregate
amount of Consolidated Interest
             Expense for such period, (b) the aggregate amount of
letter of credit fees paid during such
             period, (c) the aggregate amount of income tax
expense for such period, (d) all amounts
             attributable to Net Depreciation and amortization
for such period, and (e) all other non-cash
             charges, minus, all cash dividends paid during such
period, all determined on a consolidated
             basis with respect to Borrower and its subsidiaries
in accordance with GAAP.  "Net Income"
             means, for any period, net income or loss (after
income taxes) of Borrower and its
             subsidiaries for such period determined on a
consolidated basis in accordance with GAAP,
             provided, there shall be excluded (a) extraordinary
gains, (b) gains due to sales or write-up of
             assets, (c) earnings of any entity newly acquired,
if earned prior to acquisition, and (d) gains
             due to acquisitions of any securities of any entity. 
"Interest Expense" means, for any period,
             the interest expense, both expensed and capitalized
(including the interest component in
             respect of capital lease obligations), accrued or
paid by Borrower and its subsidiaries during
             such period, determined on a consolidated basis in
accordance with GAAP.   Net
             Depreciation  means depreciation expense during such
period determined on a consolidated
             basis in accordance with GAAP, less $500,000 for
capital expenditures.

                          4.9           Quick Asset Ratio. 
Borrower shall maintain at all times a ratio of Quick
             Assets to Adjusted Current Liabilities of not less
than .75 to 1.0.  "Quick Assets" means the
             sum of (a) cash on hand or on deposit in banks, (b)
readily marketable securities issued by the
             United States, (c) readily marketable commercial
paper rated "A-1" by Standard & Poors
             Corporation (or a similar rating by any similar
organization which rates commercial paper),
             (d) certificates of deposit or banker s acceptances
issued by commercial banks of recognized
             standing operating in the United States, and (e)
receivables not more than 90 days overdue. 
             "Adjusted Current Liabilities" means current
liabilities determined in accordance with GAAP
             excluding the Principal Debt outstanding at any
time.

                          4.10          Minimum Tangible Net
Worth.  Borrower shall maintain at all times a
             Tangible Net Worth of not less than the sum of the
following:

                          (a) $20,000,000; plus

                          (b) 50% of Net Income for which purpose
Net Income is a
                          positive number measured cumulatively
for each fiscal year beginning
                          with the fiscal year ending October 30,
1998; plus 

                          (c) 100% of the net proceeds of any
offering of any equity
                          securities sold for the account of
Borrower and otherwise permitted by
                          the terms hereof and consummated after
the date hereof; plus
<PAGE>
                          (d) 100% of any capital contributions
made to Borrower after
                          the date hereof.

              Tangible Net Worth  means the amount by which total
assets exceed total liabilities, total
             assets and total liabilities each being determined
on a consolidated basis in accordance with
             GAAP consistent with those applied in the
preparation of the financial statements previously
             furnished to Bank referred to in Section 8.2,
excluding however, from the determination of
             total assets all assets which would be classified as
intangible assets under GAAP, including
             without limitation, good will, licenses, patents,
trademarks, trade names, copyrights, and
             franchises.

                          4.11          Consecutive Losses. 
Borrower will not realize any negative Net Income in
             any two consecutive fiscal quarters.

             5.0          Affirmative Covenants.  Until full
payment and performance of all Obligations of
Borrower under the Loan Documents, Borrower will, unless Bank
consents otherwise in writing (and
without limiting any requirement of any other Loan Document):

                          5.1           Financial Statements and
Other Information. Deliver or cause to be
             delivered to Bank (a) quarterly consolidated and
consolidating financial statements of
             Borrower within forty-five (45) days after the end
of the first three fiscal quarters of each
             fiscal year, and annual audited consolidated
financial statements of Borrower within one
             hundred twenty (120) days after the end of each
fiscal year, in each instance to include a
             balance sheet, an income statement, a statement of
cash flows and such other financial
             statements and supporting schedules or documentation
reasonably requested by Bank, prepared
             in accordance with generally accepted accounting
principles consistently applied and presented
             in a format reasonably acceptable to Bank, and (b)
such additional information, reports and
             statements with respect to the business operations
and financial condition of Borrower as Bank
             may reasonably request from time to time, and (c)
within one hundred twenty (120) days after
             the end of each fiscal year, and within forty-five
(45) days after the end of the first three
             fiscal quarters of each fiscal year, a compliance
certificate in the form of Exhibit B attached
             hereto, and (d) immediately after the filing
thereof, copies of any report, proxy statement,
             financial statement, or other filing made by
Borrower with the Securities and Exchange
             Commission, any state securities agency, or any
national stock exchange or quotation service,
             and promptly upon receipt thereof, copies of any
notices received from the Securities and
             Exchange Commission or any state securities agency
relating to any order, rule, statute, or
             other laws or information that could have a Material
Adverse Effect.
<PAGE>
                          5.2           Adverse Conditions or
Events.  Promptly advise Bank in writing of (i) any
             condition, event or act which comes to its attention
that could or can reasonably be expected
             to have a Material Adverse Effect, (ii) any
litigation filed by or against Borrower or any
             Guarantor involving an amount in excess of $500,000,
(iii) the occurrence of any Event of
             Default, or of any Potential Default, or the failure
of Borrower or any Guarantor to observe
             any of its undertakings hereunder or under any of
the other Loan Documents, (iv) any
             uninsured or partially uninsured loss through fire,
theft, liability or property damage in excess
             of an aggregate of $500,000,  (v) any and all
enforcement, cleanup, remedial, removal or
             other governmental or regulatory actions instituted,
completed or threatened pursuant to any
             applicable federal, state or local laws, ordinances
or regulations relating to any Hazardous
             Materials affecting the business operations of
Borrower or any Guarantor, (vi) all claims made                   
      
             or threatened by any third party against Borrower or
any Guarantor relating to damages,
             contribution, cost recovery, compensation, loss or
injury resulting from any Hazardous
             Materials, (vii) any circumstances that constitute
grounds entitling the PBGC to institute
             proceedings to terminate a Plan subject to ERISA,
and the receipt of any notice to Borrower
             or any Commonly Controlled Entity that the PBGC
intends to terminate a Plan, and the
             receipt of notice concerning the imposition of
withdrawal liability in excess of $25,000 with
             respect to Borrower or any Commonly Controlled
Entity; and (viii) the formation or
             acquisition of any subsidiary and the occurrence of
any event which will require the execution
             of Guaranty Agreements pursuant to Section 2.4
hereof.

                          5.3           Taxes and Other
Obligations. Pay all of its taxes, assessments and other
             obligations, including, but not limited to taxes,
costs or other expenses arising out of this
             transaction, as the same become due and payable,
except to the extent the same are being
             contested in good faith by appropriate proceedings
in a diligent manner.

    5.4  Insurance. Maintain insurance with responsible insurance
companies on
    such of its properties, in such amounts and against such
risks as is customarily maintained
    by similar businesses operating in the same vicinity,
specifically to include fire and extended
    coverage insurance covering all assets, business interruption
insurance, workers
    compensation insurance and liability insurance, all providing
for at least 30 days prior
    notice to Bank of any cancellation thereof.  Satisfactory
evidence of such insurance will be
    supplied to Bank at closing, thereafter as and when requested
by Bank, and 30 days prior to
    each policy renewal.

    5.5  Existence and Compliance.  (a) Maintain its existence,
good standing and
    qualification to do business, in each jurisdiction in which,
under then applicable law, the
    nature of its business and the ownership of its properties
require such qualification and the
    failure to so qualify would have a Material Adverse Effect;
and (b) comply with all laws,
    regulations and governmental requirements including, without
limitation, environmental laws
    applicable to it or to any of its property, business
operations and transactions, a breach of
    which (when considered alone or when aggregated with the
effect of other breaches) could
    have a Material Adverse Effect.

    5.6  Maintenance. Maintain all of its tangible property in
good condition and
    repair and make all necessary replacements thereof, and
preserve and maintain all licenses,
    trademarks, privileges, permits, franchises, certificates and
the like necessary for the
    operation of its business.

    5.7  Inspection of Books and Records.  Allow any
representative of Bank to
    examine its books of record and account and to discuss its
affairs, finances and accounts with
    any of its officers, directors, employees and agents, all at
such reasonable times and as often
    as Bank may reasonably request. 

    5.8  Audits.  Submit to, and bear the expense of (except that
Borrower shall not
    be required to pay more than $10,000 of such expenses in any
period of 12 consecutive
    months), such audits and inspections as Bank may from time to
time reasonably request.
<PAGE>
    5.9  Further Assurances.  Make, execute or endorse,
acknowledge and deliver or
    file or cause the same to be done, all such vouchers,
invoices, notices, certifications and
    additional agreements, undertakings, conveyances, deeds of
trust, mortgages, assignments,
    financing statements or other assurances, and take any and
all such other action as Bank may
    from time to time reasonably request in connection with this
Agreement or any of the other
    Loan Documents (a) to cure any defects in the creation of the
Loan Documents, or (ii) to
    correct any omissions in the Loan Documents. 

    6.0  Negative Covenants.  Until full payment and performance
of all Obligations of
Borrower under the Loan Documents, Borrower will not, without the
prior written consent of Bank
(and without limiting any requirement of any other Loan
Documents):

    6.1  Capital Expenditures.  Make capital expenditures during
each fiscal year
    (including capitalized leases) in excess of $7,500,000.

    6.2  Lease Expenditures.  Incur new obligations for the lease
or hire of real or
    personal property in any fiscal year in excess of an
aggregate of $1,000,000.

    6.3  Transfer of Assets.  Convey, assign, transfer, sell,
lease or otherwise dispose
    of in one transaction or a series of transactions (or agree
to do any of the foregoing at any
    future time) all or substantially all or a substantial part
of its properties or assets (whether
    now owned or hereafter acquired) or any part of such
properties or assets which are essential
    to the conduct of its business substantially as now
conducted.

    6.4  Merger, Etc.  Enter into any merger or consolidation,
except that Borrower
    may merge into or consolidate with any of its subsidiaries so
long as Borrower is the
    survivor.

    6.5  Liens.  Grant, suffer or permit any contractual or
noncontractual lien on or
    security interest in its assets, except Permitted Liens.

    6.6  Extensions of Credit.  Make, or permit any Guarantor to
make, any loan or
    advance to any person or entity, or purchase or otherwise
acquire, or permit any Guarantor to
    purchase or otherwise acquire, any capital stock, assets,
obligations or other securities of, or
    make any capital contribution to, or otherwise invest in or
acquire any interest in any entity;
    provided that Borrower may acquire or invest in entities
where the cumulative aggregate cash
    and/or stock consideration does not exceed $10,000,000 over
the term of this Agreement.

    6.7  Borrowings. Create, incur, assume or become liable in
any manner for any
    indebtedness (whether direct or contingent, for borrowed
money, deferred payment for the
    purchase of assets, lease payments, as surety or guarantor
for the debt for another, or
    otherwise) other than to Bank, except for (i) normal trade
debts incurred in the ordinary
    course of Borrower's business, (ii) purchase-money debt up to
$500,000 in the aggregate at
    any time outstanding, (iii) lease expenditures permitted by
Section 7.2 hereof, and (iv)
    existing indebtedness disclosed to Bank in writing and
acknowledged by Bank prior to the date
    of this Agreement.

    6.8  Dividends and Distributions. Make any distribution
(other than dividends
    payable in capital stock of Borrower) on any shares of any
class of its capital stock, or
    apply any of its property or assets to the purchase,
redemption or other retirement of any
    shares of any class of capital stock of Borrower exceeding in
the aggregate 50% of net
    profit per fiscal year.
<PAGE>
    6.9  Change of Character of Business or Location.  Change the
general
    character of business as conducted at the date hereof, or
engage in any type of business not
    reasonably related to its business as presently conducted, or
fail to maintain in Texas its
    principal place of business, its primary administrative
office, and its billing and collection
    operations.
 .
    6.10 Principal Debt not to Exceed Commitment.  Permit at any
time the
    Principal Debt to exceed the Commitment.

    6.11 Change of Control.  Permit the change of control of
Borrower.  "Change of
    control" as used in the preceding sentence means the
acquisition by a third party of more than
    fifty percent (50%) of the outstanding voting stock of
Borrower.

    6.12 Arm's Length Transactions.  Enter into a transaction
with any affiliate (other
    than services rendered by an officer, employee or director),
except a transaction upon terms
    that are not less favorable to it than would be obtained in a
transaction negotiated at arm's
    length with an unrelated third party.

    7.0  Representations and Warranties.  Borrower hereby
represents and warrants to Bank
as follows:

    7.1  No Liens.  Borrower and each Guarantor have good and
defensible title to all
    of their assets, and none of such assets are subject to any
security interest, mortgage, deed of
    trust, pledge, lien, title retention document or encumbrance
of any character, except for
    Permitted Liens.

    7.2  Financial Statements.   The financial statements of
Borrower dated as of
    July 31, 1997, have been prepared in accordance with
generally accepted accounting
    principles on a consistent basis throughout the period
involved and fairly present Borrower s
    financial condition as of the date or dates thereof, and
there have been no material adverse
    changes in Borrower s financial condition or operation since
the date or dates thereof.

    7.3  Good Standing.  Borrower is a corporation, duly
organized, validly existing
    and in good standing under the laws of Delaware and has the
power and authority to own its
    property and to carry on its business in Texas and in every
other state in which, under
    presently applicable law, the nature of its property or
business requires such qualification and
    in which the failure to be so qualified would (when
considered alone or when aggregated with
    the effect of failure to qualify in all other jurisdictions)
have a Material Adverse Effect.


    7.4  Binding Agreements.  This Agreement and the other Loan
Documents
    executed by Borrower constitute valid and legally binding
obligations of Borrower,
    enforceable in accordance with their terms.  Each of the Loan
Documents executed by each
    Guarantor constitutes the valid and binding obligation of
such Guarantor, enforceable in
    accordance with its terms.
<PAGE>
    7.5  Litigation.  There is no proceeding involving Borrower
or any Guarantor
    pending or, to the knowledge of Borrower, threatened before
any court or governmental
    authority, agency or arbitration authority, except as
disclosed to Bank in writing and
    acknowledged by Bank prior to the date of this Agreement.

    7.6  No Conflicting Agreements.  There is no charter, bylaw,
stock provision,
    partnership agreement or other document pertaining to the
power or authority of Borrower or
    any Guarantor and no provision of any existing agreement,
mortgage, indenture or contract
    binding on Borrower or any Guarantor or affecting any
property of Borrower or any
    Guarantor, which would conflict with or in any way prevent
the execution, delivery or
    carrying out of the terms of this Agreement and the other
Loan Documents.

    7.7  Taxes.  All taxes and assessments due and payable by
Borrower and any
    Guarantor have been paid or are being contested in good faith
by appropriate proceedings in a
    diligent manner, and the Borrower and Guarantors have filed
all tax returns which they are
    required to file.

    7.8  Accuracy of Information.  To the best of Borrower's
knowledge, all factual
    information furnished to Bank in connection with this
Agreement and the other Loan
    Documents is and will be accurate and complete in all
material respects on the date as of
    which such information is delivered to Bank and is not and
will not be incomplete by the
    omission of any material fact necessary to make such
information not misleading.

    7.9  ERISA.  Borrower is in compliance in all material
respects with all applicable
    provisions of ERISA.  Neither a Reportable Event nor a
Prohibited Transaction has occurred
    and is continuing with respect to any Plan; no notice of
intent to terminate a Plan has been
    filed, nor has any Plan been terminated; neither Borrower nor
any Commonly Controlled
    Entity has completely or partially withdrawn from a
Multiemployer Plan; and Borrower and
    each Commonly Controlled Entity have met their minimum
funding requirements under
    ERISA with respect to all of their Plans.

    7.10 Environmental.  The conduct of Borrower s business
operations and the
    condition of Borrower s property does not and will not
violate any federal laws, rules or
    ordinances for environmental protection, or regulations of
the Environmental Protection
    Agency, or any applicable local or state law, rule,
regulation or rule of common law, or any
    judicial interpretation thereof relating primarily to the
environment or Hazardous Materials.

    7.11 Subsidiaries.  Borrower has no subsidiaries other than
the Mexican
    Subsidiaries, Optek Holdings, Inc. and OTX Corporation.

    7.12 Continuation of Representations and Warranties.  All
representations and
    warranties made under this Agreement shall be deemed to be
made at and as of the date
    hereof and at and as of the date of any future Loan and in
all instances shall be true and
    correct (except to the extent that such representations and
warranties relate solely to an earlier
    date).

    8.0  Default.  Any of the following shall constitute events
of default (each an  Event of
Default ):
<PAGE>
    8.1  Nonpayment.  (a) Borrower shall default in the due and
punctual payment of
    any principal or interest of the Note when due and payable,
whether at maturity or otherwise,
    or (b) Borrower or any Guarantor shall default in the due and
punctual payment of any of the
    other Obligations when due and payable.

    8.2  Representations and Warranties.  Any representation,
warranty or statement
    made by Borrower or any Guarantor herein or otherwise in
writing in connection herewith or
    in connection with any of the other Loan Documents and the
agreements referred to herein or
    therein or in any financial statement, certificate or
statement signed  by any officer or
    employee of Borrower and furnished pursuant to any provision
of the Loan Documents shall
    be breached, or shall be materially false, incorrect or
incomplete when made.

    8.3  Default in Covenants Under Agreement. (a) Borrower shall
default in the
    due performance or observance by it of any term, covenant or
agreement set forth in the No
    Cure Period Covenants; or (b) Borrower shall default in the
due performance or observance
    of any term, covenant or agreement contained in this
Agreement other than the No Cure
    Period Covenants, and such default continues unremedied for a
period of thirty (30) days after
    notice thereof from Bank or Bank is notified of such default
or should have been so notified
    pursuant to the provisions of Section 6.2 hereof, whichever
is earlier.

    8.4  Default in Other Loan Documents.  Borrower or any
Guarantor shall default
    in the due performance of or observance by it of any term,
covenant or agreement on its part
    to be performed pursuant to the terms of any of the other
Loan Documents and the default
    shall continue unremedied beyond any grace or cure period
therein provided.

    8.5  Default in Other Debt.  An event of default shall occur
under the provisions
    of any instrument (other than the Loan Documents) evidencing
indebtedness of Borrower for
    the payment of borrowed money or of any agreement relating
thereto, the effect of which is to
    permit the holder or holders of such instrument to cause the
indebtedness evidenced by such
    instrument to become due and payable prior to its stated
maturity (whether or not the holder
    actually exercises such option).

    8.6  Validity of Loan Documents.  Any of the Loan Documents
shall cease to be
    a legal, valid and binding agreement enforceable against any
party executing the same in
    accordance with the respective terms thereof, or shall in any
way be terminated, or become or
    be declared ineffective or inoperative by operation of law,
or shall in any way whatsoever
    cease to give or provide the respective rights, remedies,
powers and privileges intended to be
    created thereby.

    8.7  Bankruptcy.  Borrower or any Guarantor shall suspend or
discontinue its
    business operations, or shall generally fail to pay its debts
as they mature, or shall file a
    petition commencing a voluntary case concerning Borrower
under any chapter of the United
    States Bankruptcy Code; or a court of competent jurisdiction
enters an order or decree under
    any bankruptcy law that remains unstayed and in effect for
forty-five (45) days that is for
    relief against Borrower or any Guarantor in an involuntary
case or appoints a custodian of
    Borrower or any Guarantor for all or substantially all of its
property; or Borrower or any
    Guarantor shall become insolvent (howsoever such insolvency
may be evidenced).
<PAGE>
    8.8  Judgments and Decrees.  Borrower or any Guarantor shall
suffer a final
    judgment for the payment of money in excess of $500,000 and
shall not discharge the same
    within a period of thirty (30) days unless, pending further
proceedings, execution has not been
    commenced, or, if commenced, has been effectively stayed. 
Any order, judgment or decree
    shall be entered in any proceeding against Borrower or any
Guarantor decreeing the
    dissolution or split up of such entity and such order shall
remain undischarged or unstayed for
    a period in excess of thirty (30) days.

    8.9  ERISA.  Any of the following events shall occur or exist
with respect to
    Borrower and any Commonly Controlled Entity under ERISA and
the regulations
    promulgated thereunder:

             (a)  any Reportable Event shall occur; 

             (b)  complete or partial withdrawal from any
Multiemployer Plan shall
         take place;

             (c)  any Prohibited Transaction shall occur; 

             (d)  a notice of intent to terminate a Plan shall be
filed, or a Plan shall
         be terminated; or 

             (e)  circumstances shall exist which constitute
grounds entitling the
         PBGC to institute proceedings to terminate a Plan, or
the PBGC shall institute such
         proceedings;

    and in each case above, such event or condition, together
with all other events or
    conditions, if any, could subject Borrower to any tax,
penalty or other liability which in the
    aggregate may exceed $25,000.

    9.0  Remedies.  Upon the occurrence of an Event of Default
described in Section 9.7
hereof, the entire principal of and accrued interest on the Note
shall forthwith be due and payable
without demand, presentment for payment, notice of nonpayment,
protest, notice of protest, notice of
intent to accelerate, notice of acceleration and all other
notices and further actions of any kind, all of
which are hereby expressly waived by Borrower.  In the event that
any other Event of Default occur
and be continuing, Bank may, without demand or notice of its
election terminate its obligation to
make further Loans hereunder and/or declare the entire unpaid
balance of the Note and all other
indebtedness of Borrower to Bank, or any part thereof,
immediately due and payable, whereupon the
principal of and accrued interest on such Note and other
indebtedness shall be forthwith due and
payable without demand, presentment for payment, notice of
nonpayment, protest, notice of protest,
notice of intent to accelerate, notice of acceleration and all
other notices and further actions of any
kind, all of which are hereby expressly waived by Borrower.  Upon
the occurrence and during the
continuance of any Event of Default, Bank may (a) exercise any
and all rights under or pursuant to
any of the Loan Documents, and (b) exercise any and all rights
afforded to Bank by the laws of the
State of Texas or any other applicable jurisdiction or in equity
or otherwise, as Bank may deem
appropriate, and (c) terminate the Commitment.
<PAGE>
    10.0 Notices.  All notices, requests or demands which any
party is required or may desire
to give to any other party under any provision of this Agreement
must be in writing (including
telegraphic, telex and facsimile transmission) delivered to the
other party at the addresses set forth on
the first page of this Agreement or to such other address as any
party may designate by written notice
to the other party.  Each such notice, request and demand shall
be deemed given or made (whether
actually received or not) (a) if sent by mail, upon the earlier
of the date of receipt or five (5) days
after deposit in the U.S. Mail, first class postage prepaid, and
(b) if sent by any other means, upon
delivery.  Unless otherwise changed by notice given pursuant to
this Section, the facsimile
transmission number for Borrower shall be (972) 323-2208, and the
facsimile transmission number for
Bank shall be (214) 508-3139.

    11.0 Costs, Expenses and Attorneys' Fees.  Each party shall
bear its own attorneys fees
incurred by it in connection with the negotiation and preparation
of this Agreement and each of the
Loan Documents executed as part of the initial closing.  Borrower
shall pay to Bank immediately
upon demand the full amount of all costs and expenses, including
reasonable attorneys' fees (including
outside counsel fees but excluding any allocation of costs of
Bank s in-house counsel), incurred by
Bank in connection with (a) if initiated or requested by
Borrower, any modifications of or consents or
waivers under or amendments to this Agreement, the Note, the
other Loan Documents and the
agreements described therein, and (b) all other costs and
attorneys  fees incurred by Bank for which
Borrower is obligated to pay in accordance with the terms of the
Loan Documents.  Borrower further
agrees to pay on demand all costs and expenses of Bank incurred
in connection with the enforcement
(whether through negotiations, legal proceedings or otherwise) of
the Loan Documents.  Borrower
further agrees to indemnify Bank and its employees and agents,
from and hold it harmless against any
and all losses, liabilities, claims, damages or expenses which
any of them suffers or incurs as a result
of its entering into this Agreement, or the consummation of the
transactions contemplated by this
Agreement and the Loan Documents, or the use or contemplated use
of the proceeds of the Loan, or
due to a release or alleged release of Hazardous Materials,
including, without limitation, the fees and
disbursements of counsel incurred in connection with any
litigation, arbitration or other proceeding
arising out of or by reason of any of the aforesaid.  Borrower
shall defend any claim for which an
indemnified party is entitled to seek indemnity pursuant to the
preceding sentence, and the
indemnified party shall cooperate with the defense.  The
indemnified party may have separate
counsel, and Borrower will pay the expenses and reasonable fees
of such separate counsel if either
counsel for Borrower or counsel for the indemnified party shall
advise the indemnified party that the
interests of both Borrower and the indemnified party with respect
to such claim are or with reasonable
certainty will become adverse.

    12.0 Miscellaneous.  Borrower and Bank further covenant and
agree as follows, without
limiting any requirement of any other Loan Document:

    12.1 Cumulative Rights and No Waiver.  Each and every right
granted to Bank
    under any Loan Document, or allowed it by law or equity shall
be cumulative of each other
    and may be exercised in addition to any and all other rights
of Bank, and no delay in
    exercising any right shall operate as a waiver thereof, nor
shall any single or partial exercise
    by Bank of any right preclude any other or future exercise
thereof or the exercise of any other
    right.  Borrower expressly waives any presentment, demand,
protest or other notice of any
    kind, including but not limited to notice of intent to
accelerate and notice of acceleration.  No
    notice to or demand on Borrower in any case shall, of itself,
entitle Borrower to any other or
    future notice or demand in similar or other circumstances.
<PAGE>
    12.2 Choice of Law and Venue.   THIS AGREEMENT SHALL BE
    CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS (BUT
    NOT THE RULES GOVERNING CONFLICTS OF LAWS) OF THE STATE OF
    TEXAS AND SHALL BE PERFORMABLE IN DALLAS COUNTY, TEXAS.

    12.3 Amendment.  No modification, consent, amendment or
waiver of any
    provision of this Agreement, nor consent to any departure by
a party therefrom, shall be
    effective unless the same shall be in writing and signed by
an officer of the other party, and
    then shall be effective only in the specified instance and
for the purpose for which given. 
    This Agreement is binding upon the parties, their successors
and assigns, and inures to the
    benefit of the parties, their successors and assigns;
however, no assignment or other transfer
    of Borrower's rights or obligations hereunder shall be made
or be effective without Bank's
    prior written consent, nor shall it relieve Borrower of any
obligations hereunder.  There is no
    third party beneficiary of this Agreement.

    12.4 Documents.  All documents, certificates and other items
required under this
    Agreement to be executed and/or delivered to Bank shall be in
form and content satisfactory
    to Bank and its counsel.

    12.5 Partial Invalidity.  The unenforceability or invalidity
of any provision of this
    Agreement shall not affect the enforceability or validity of
any other provision herein and the
    invalidity or unenforceability of  any provision of any Loan
Document to any person or
    circumstance shall not affect the enforceability or validity
of such provision as it may apply to
    other persons or circumstances.

    12.6 Survivability.  All covenants, agreements,
representations and warranties
    made herein or in the other Loan Documents shall survive the
making of the initial Loan and
    shall continue in full force and effect so long as the
Obligations are outstanding or the
    Commitment has not expired.

    12.7 Accounting Terms.  Unless specified elsewhere herein,
all accounting terms
    used herein shall be interpreted, all accounting
determinations hereunder shall be made, and
    all financial statements to be delivered hereunder shall be
prepared in accordance with GAAP.

    12.8 Expiration of Commitment/Renewal.  The Commitment of
Bank hereunder
    shall expire on the Maturity Date.  Bank is under no express
or implied duty or obligation to
    renew the Note or extend the Maturity Date.
<PAGE>
    12.9 Environmental.  Borrower shall immediately notify Bank
of any
    remedial action taken by Borrower under environmental laws
with respect to
    Borrower's business operations.  Borrower will not use or
permit any other party to
    use any Hazardous Materials at any of Borrower's places of
business or at any
    other property owned by Borrower except such materials as are
incidental to
    Borrower's normal course of business, maintenance and repairs
and which are
    handled in compliance with all applicable environmental laws.
Borrower agrees to
    permit Bank, its agents, contractors and employees to enter
and inspect any of
    Borrower's places of business or any other property of
Borrower at any reasonable
    times upon three (3) days prior notice for the purposes of
conducting an
    environmental investigation and audit (including taking
physical samples) to insure
    that Borrower is complying with this covenant and Borrower
shall reimburse Bank
    on demand for the costs of any such environmental
investigation and audit not to
    exceed $10,000 per year.  Borrower shall provide Bank, its
agents, contractors,
    employees and representatives with access to and copies of
any and all data and
    documents relating to or dealing with any Hazardous Materials
used, generated,
    manufactured, stored or disposed of by Borrower's business
operations within five
    (5) days of the request therefore. 

    13.0 Agreement Controlling.  In the event of a conflict
between the terms and provisions
of this Agreement and the terms and provisions of any of the
other Loan Documents, the terms and
provisions of this Agreement shall control.

    14.0 Arbitration.  ANY CONTROVERSY OR CLAIM BETWEEN OR AMONG
THE
PARTIES HERETO ARISING OUT OF OR RELATING TO THIS INSTRUMENT,
AGREEMENT
OR DOCUMENT OR ANY RELATED INSTRUMENTS, AGREEMENTS OR DOCUMENTS,
INCLUDING ANY CLAIM BASED ON OR ARISING FROM AN ALLEGED TORT,
SHALL BE
DETERMINED BY BINDING ARBITRATION IN ACCORDANCE WITH THE FEDERAL
ARBITRATION ACT (OR IF NOT APPLICABLE, THE APPLICABLE STATE LAW). 
THE
RULES OF PRACTICE AND PROCEDURE FOR THE ARBITRATION OF COMMERCIAL
DISPUTES OF J.A.M.S./ENDISPUTE OR ANY SUCCESSOR THEREOF
(J.A.M.S.), AND THE
"SPECIAL RULES" SET FORTH BELOW.  IN THE EVENT OF ANY
INCONSISTENCY, THE
SPECIAL RULES SHALL CONTROL.  JUDGMENT UPON ANY ARBITRATION AWARD
MAY
BE ENTERED IN ANY COURT HAVING JURISDICTION.  ANY PARTY TO THIS
INSTRUMENT, AGREEMENT OR DOCUMENT MAY BRING AN ACTION, INCLUDING
A
SUMMARY OR EXPEDITED PROCEEDING, TO COMPEL ARBITRATION OF ANY
CONTROVERSY OR CLAIM TO WHICH THIS AGREEMENT APPLIES IN ANY COURT
HAVING JURISDICTION OVER SUCH ACTION.

    14.1 Special Rules.  THE ARBITRATION SHALL BE CONDUCTED IN
THE
    CITY OF BORROWER S DOMICILE AT THE TIME OF THE EXECUTION OF
THIS
    INSTRUMENT, AGREEMENT OR DOCUMENT, AND ADMINISTERED BY
J.A.M.S.
    WHO WILL APPOINT AN ARBITRATOR; IF J.A.M.S. IS UNABLE OR
LEGALLY
    PRECLUDED FROM ADMINISTERING THE ARBITRATION, THEN THE
AMERICAN
    ARBITRATION ASSOCIATION WILL SERVE.  ALL ARBITRATION HEARINGS
WILL
    BE COMMENCED WITHIN 90 DAYS OF THE DEMAND FOR ARBITRATION;
    FURTHER, THE ARBITRATOR SHALL ONLY, UPON A SHOWING OF CAUSE,
BE
    PERMITTED TO EXTEND THE COMMENCEMENT OF SUCH HEARING FOR UP
TO
    AN ADDITIONAL 60 DAYS.
<PAGE>
    14.2 Reservation of Rights.  NOTHING IN THIS ARBITRATION
PROVISION
    SHALL BE DEEMED TO (I) LIMIT THE APPLICABILITY OF ANY
OTHERWISE
    APPLICABLE STATUTES OF LIMITATION OR REPOSE AND ANY WAIVERS
    CONTAINED IN THIS INSTRUMENT, AGREEMENT OR DOCUMENT; OR (II)
BE A
    WAIVER BY THE BANK OF THE PROTECTION  AFFORDED TO IT BY 12
U.S.C.
    SEC. 91 OR ANY SUBSTANTIALLY EQUIVALENT STATE LAW; OR (III)
LIMIT THE
    RIGHT OF THE BANK HERETO (A) TO EXERCISE SELF HELP REMEDIES
SUCH AS
    (BUT NOT LIMITED TO) SETOFF, OR (B) TO FORECLOSE AGAINST ANY
REAL OR
    PERSONAL PROPERTY COLLATERAL, OR (C) TO OBTAIN FROM A COURT
    PROVISIONAL OR ANCILLARY REMEDIES SUCH AS (BUT NOT LIMITED
TO)
    INJUNCTIVE RELIEF, WRIT OF POSSESSION OR THE APPOINTMENT OF A
    RECEIVER, OR (IV) LIMIT THE RIGHTS OF THE PARTIES HERETO
UNDER THE
    BANKRUPTCY CODE OR SIMILAR LAWS AFFECTING THE RIGHTS OF
CREDITORS
    GENERALLY.  THE BANK MAY EXERCISE SUCH SELF HELP RIGHTS,
FORECLOSE
    UPON SUCH PROPERTY, OR OBTAIN SUCH PROVISIONAL OR ANCILLARY
    REMEDIES BEFORE, DURING OR AFTER THE PENDENCY OF ANY
ARBITRATION
    PROCEEDING BROUGHT PURSUANT TO THIS INSTRUMENT, AGREEMENT OR
    DOCUMENT.  NEITHER THIS EXERCISE OF SELF HELP REMEDIES NOR
THE
    INSTITUTION OR MAINTENANCE OF AN ACTION FOR FORECLOSURE OR
    PROVISIONAL OR ANCILLARY REMEDIES SHALL CONSTITUTE A WAIVER
OF
    THE RIGHT OF ANY PARTY, INCLUDING THE CLAIMANT IN ANY SUCH
ACTION,
    TO ARBITRATE THE MERITS OF THE CONTROVERSY OR CLAIM
OCCASIONING
    RESORT TO SUCH REMEDIES.


    IN WITNESS WHEREOF, the parties have executed this Agreement
as of the date and year
first above written.






OPTEK TECHNOLOGY, INC.



By                                                                
        

     Title                                                        
        












NATIONSBANK OF TEXAS, N.A.



By                                                                
        
    Ronald K. Baker
    Senior Vice President






                 LIST OF EXHIBITS

A. . . . . . . . . Borrowing and Interest Notice Request . . . .
 . .   2.1

B. . . . . . . . . . . . .Compliance Certificate . . . . . . . .
 . .   6.1
    14.3PAGE
<PAGE>
                                 EXHIBIT A

                   BORROWING AND INTEREST NOTICE REQUEST

    Reference is made to that certain Loan Agreement between
OPTEK TECHNOLOGY, INC.
and NATIONSBANK OF TEXAS, N.A. dated as of January 29, 1998 (the
"Loan Agreement"). 
The terms used herein shall have the same meanings as provided
therefor in the Loan Agreement
unless the context hereof otherwise requires or provides. 

A.  AVAILABILITY.

     1. Enter: Amount of Commitment
                    $10,000,000                                   
        
     
     2.      Enter:  Principal Debt outstanding 
             as of this date.                                     
        
     
     3.      Excess (deficit) available for Loans 
             (subtract line A2 from line A1).                     
        
     
     
   4.   Description of use of proceeds of Loan:                   
        

                                                                 
          
                                                                  
        
          
          5.      The Borrower hereby certifies that all
conditions precedent specified by the Loan
             Agreement for this Loan have been complied with in
all respects.
     
     B. FLOATING BASE LOAN.

   1.   Amount of Floating Base Rate loan:            
____________________

   2.   Type of Floating Base loan

        New Floating Base loan

        Conversion of LIBO Rate loan to 
   Floating Base loan

   3.   Date of funding or conversion                 
____________________

PAGE
<PAGE>
C. LIBO RATE LOAN.

   1.   Amount of LIBO Rate loan (minimum of $500,000 
   and in $100,000 increments thereafter)             
____________________

   2.   Type of LIBO Rate loan

        New LIBO Rate loan

        Renewal of existing LIBO Rate loan

        Conversion of Floating Base Rate loan to LIBO Rate loan

   3.   Date of funding or renewal or conversion      
____________________

   4.   LIBO Interest Period (30 days, 60 days or 90
days)____________________


   The Borrower hereby certifies that on the date hereof the
representations and warranties
contained the Loan Agreement are true in all material respects as
if made on the date hereof (except
to the extent that such representations and warranties relate
solely to an earlier date), and no Event of
Default or Potential Default exists.

   Dated ____________, 199__. 

   OPTEK TECHNOLOGY, INC.



   By                                                             
        

      Title                                                       
        
   14.4PAGE
<PAGE>
                                 EXHIBIT B

                          COMPLIANCE CERTIFICATE


TO:NATIONSBANK OF TEXAS, N.A.


   Reference is made to that certain Loan Agreement between OPTEK
TECHNOLOGY, INC.
and NATIONSBANK OF TEXAS, N.A. dated as of January 29, 1998 (the
"Loan Agreement"). 
The terms used herein shall have the same meanings as provided
therefor in the Loan Agreement,
unless the context hereof otherwise requires or provides.

   The undersigned HEREBY CERTIFIES that he is the duly elected
and qualified officer of
_________________________ holding the office set forth opposite
his signature below, AND DOES
FURTHER CERTIFY, individually and on behalf of the Borrower,
that:

   1.   Attached hereto are complete and detailed financial
statements of the Borrower
   as of, and for the period ending _________________, 199__,
which are complete and correct
   in all respects.

   2.   A review of the activities of the Borrower during the
preceding fiscal quarter
   has been made under his supervision with a view to determining
whether, during such fiscal
   quarter, Borrower has kept, observed, performed and fulfilled
all of its obligations under the
   Loan Documents, and that to the best of his knowledge Borrower
has kept, observed,
   performed and fulfilled all of such obligations, except as set
forth in Schedule I attached
   hereto.  (If no Schedule I is attached, then such exception
does not apply and no such failures
   exist.)

   3.   Set forth below is the calculation of the financial
covenants of the Loan
   Agreement determined as of the last day of the immediately
preceding fiscal quarter of the
   Borrower, which calculations have been made in accordance with
the requirements of the
   Loan Agreement and which are true and correct in all material
respects.

   A.   Leverage Ratio.  Borrower will not permit its ratio of
Total Funded Debt as of the last
        day of each fiscal quarter to EBITDA for the period of
four consecutive fiscal quarters
        ending on such day to be greater than 2.0 to 1.0  The
leverage ratio of Borrower as
        of the last day of the date set forth above for the
period of four consecutive fiscal
        quarters ending on such day is:

        (1) Computation of EBITDA

   Net Income, plus                                            
$__________

   Consolidated Interest Expense, plus                         
$__________

   Aggregate Letter of Credit Fees, plus                       
$__________

   Aggregate Income Tax Expense, plus                          
$__________

   Net Depreciation, plus                                      
$__________

   15.      Amortization, plus                                 
$__________

   All other non-cash charges, minus                           
$__________

   Cash dividends, minus                                       
$__________

   Extraordinary gains                                         
$__________

   EBITDA                                                      
$__________

   (2)  Total Funded Debt                                      
$__________

   (3)  Leverage Ratio (Total Funded Debt
   divided by EBITDA)                                       
_____ to _____

   B.   Quick Asset Ratio.  Borrower will at all times maintain a
ratio of Quick Assets to
        Adjusted Current Liabilities of not less than .75 to 1.0. 
Such ratio as of the date
        above is:

   (1)  Computation of Quick Assets

   Cash on hand or on deposit, plus                            
$__________

   Readily marketable securities issued by U.S., plus          
$__________

   Readily marketable commercial paper rated
   "A-1", plus                                                 
$__________

   Certificates of deposit/banker s acceptances, plus          
$__________

   Receivables not more than 90 days overdue                   
$__________

   Quick Assets                                                
$__________

   (2)  Computation of Adjusted Current Liabilities             
__________

        Current liabilities, less                              
$__________

        Principal debt outstanding                             
$__________

   Adjusted current liabilities                                
$__________

   (3)  Quick Asset Ratio (Quick Assets divided by
   Adjusted Current Liabilities)                            
_____ to _____

   C.   Minimum Tangible Net Worth.  Borrower must maintain at
all times a
        Tangible Net Worth of not less than the sum of (a)
$20,000,000; plus (b) 50%
        of Net Income for which purpose Net Income is a positive
number measured
        cumulatively for each fiscal year beginning with the
fiscal year ending October
        30, 1998; plus (c) 100% of the net proceeds of any
offering of any equity
        securities sold for the account of Borrower and otherwise
permitted by the
        terms hereof and consummated after January 29, 1998; plus
(d) 100% of any
        capital contributions made to Borrower after January 29,
1998.
<PAGE>
   (1)  $20,000,000 Threshold                                  
$20,000,000

   (2)  50% of Net Income for which purpose Net Income is
   a positive number measured cumulatively for
   each fiscal year beginning with the fiscal year
   ending October 30, 1998                                     
$__________

   (3)  100% of the net proceeds of any offering of any
   equity securities sold for the account of Borrower
   and otherwise permitted by the terms hereof and
   consummated after January 29, 1998                          
$__________

   (4)  100% of any capital contributions made to
   Borrower after January 29, 1998                             
$__________

   (5)  Sum of lines (1), (2), (3) and (4)                     
$__________

   (6)  Tangible Net Worth as of the date above is (amount
   on line (6) must be greater than amount on line (5)):       
$__________
   
   D.   Tangible Net Worth of Mexican Subsidiaries.

   (1)  Tangible Net Worth of Optron De Mexico, S.A. de C.V.   
$__________

   (2)  Tangible Net Worth of Semicondores Opticos, S.A. de
C.V.$__________

   (3)  Total of lines (1) and (2)                             
$__________

   (4)  Tangible Net Worth of Borrower                         
$__________

   (5)  Multiply amount on line (4) by 25%                     
$__________

   (6)  If amount on line (5) is less than
   the amount on line (3), Mexican Subsidiaries
   must guarantee Obligations.

   4.   Set forth below is the calculation of those negative
covenants contained in the
   Loan Agreement which are determined as of the last day of the
fiscal year of Borrower. 
   These calculations have been made in accordance with the
requirements of the Loan
   Agreement and are true and correct in all respects:

   A.   Capital Expenditures.  The total of all capital
expenditures during the fiscal year
        ending on the date set forth above (including capitalized
leases) were $___________.

   B.   Lease Expenditures.  The total of all new obligations for
lease or hire of real or
        personal property incurred in the fiscal year ending on
the date set forth above are
        $______________.
<PAGE>
   C.   Fifty percent of the net profits of Borrower during the
fiscal year ending on the date
        set forth above is $___________.  The aggregate of all
distributions (other than
        dividends payable in capital stock of Borrower) on any
shares of any class of
        Borrower s capital stock made during the fiscal year
ended on the date set forth above
        and the aggregate of all property or assets of Borrower
applied to the purchase or
        redemption or other retirement of its shares during the
fiscal year ending on the date
        set forth above, are $___________.


   IN WITNESS WHEREOF, the undersigned has executed this
Certificate on
________________, 199__.

Office      Signature


                                                                  
        
   Printed Name