THIRD LOAN MODIFICATION AGREEMENT

Exhibit 10.64

THIRD LOAN MODIFICATION AGREEMENT

This Third Loan Modification Agreement (this “Loan Modification Agreement”) is entered into as of June 10, 2009, by and among (a) SILICON VALLEY BANK , a California corporation, with its principal place of business at 3003 Tasman Drive, Santa Clara, California 95054 (“Bank”) and (b) FINISAR CORPORATION , a Delaware corporation, with its chief executive office located at 1399 Moffett Park Drive, Sunnyvale, California 94089 (“Finisar”) and OPTIUM CORPORATION , a Delaware corporation, with its principal place of business at 500 Horizon Drive, Suite 505, Chalfont, Pennsylvania 18914 (“Optium”) (hereinafter, Finisar and Optium are jointly and severally, individually and collectively, referred to as “Borrower”).

1. DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS, Among other indebtedness and obligations which may be owing by Borrower to Bank, Borrower is indebted to Bank pursuant to a loan arrangement dated as of March 14, 2008, evidenced by, among other documents, a certain Loan and Security Agreement dated as of March 14, 2008, among Borrower and Bank, as affected by a certain Joinder Agreement dated as of October 30, 2008, as amended by a certain First Loan Modification Agreement dated as of October 30, 2008, and as further amended by a certain Second Loan Modification Agreement dated as of February 6, 2009 (as amended and affected, the “Loan Agreement”). Capitalized terms used but not otherwise defined herein shall have the same meaning as in the Loan Agreement.

2. DESCRIPTION OF COLLATERAL. Repayment of the Obligations is secured by the Collateral as described in the Loan Agreement (together with any other collateral security granted to Bank, the “Security Documents”). Hereinafter, the Security Documents, together with all other documents evidencing or securing the Obligations shall be referred to as the “Existing Loan Documents”.

3. DESCRIPTION OF CHANGE IN TERMS .

     A. Modifications to Loan Agreement.

“Subject to the terms and conditions of this Agreement and to deduction of Reserves, Bank shall make Advances not exceeding the Availability Amount.”

and inserting in lieu thereof the following:

“Subject to the terms and conditions of this Agreement and, during an Asset Based Period, to deduction of Reserves, Bank shall make Advances not exceeding the Availability Amount.”

“As part of the Revolving Line, Bank shall issue or have issued Letters of Credit for Borrower’s account.”

and inserting in lieu thereof the following:

“As part of the Revolving Line and, during an Asset Based Period, subject to deduction of Reserves, Bank shall issue or have issued Letters of Credit for Borrower’s account.”

“As part of the Revolving Line, Borrower may enter into foreign exchange contracts with Bank under which Borrower commits to purchase from or sell to Bank a specific amount of Foreign Currency (each, a “ FX Forward Contract ”) on a specified date (the “ Settlement Date ”).”

and inserting in lieu thereof the following;

“As part of the Revolving Line and, during an Asset Based Period, subject to deduction of Reserves, Borrower may enter into foreign exchange contracts with Bank under which Borrower commits to purchase from or sell to Bank a specific amount of Foreign Currency (each, a “ FX Forward Contract ”) on a specified date (the “ Settlement Date ”).”

“ 2.2 Overadvances . If, at any time, the Credit Extensions under Sections 2.1.1, 2.1.2, 2.1.3 and 2.1.4 exceed the Revolving Line, Borrower shall immediately pay to Bank in cash such excess.”

and inserting in lieu thereof the following:

“ 2.2 Overadvances; Further Limitation .

     (a) If, at any time, the sum of (i) the outstanding principal amount of any Advances (including any amounts used for Cash Management Services), plus (ii) the face amount of any outstanding Letters of Credit (including drawn but unreimbursed Letters of Credit and any Letter of Credit Reserve), plus (iii) the FX Reserve, exceeds the lesser of either the Revolving Line or the Borrowing Base, Borrower shall immediately pay to Bank in cash such excess.

     (b) In order to have Credit Extensions outstanding that exceed Twenty-Five Million Dollars ($25,000,000.00) in the aggregate, Borrower shall provide evidence to Bank, upon Bank’s request, that it has unrestricted cash (as set forth on its balance sheet) in an amount equal to at least the sum of (i) Fifty Million Dollars ($50,000,000.00) plus (ii) the aggregate amount of Credit Extensions outstanding at such time. Borrower shall be required to comply with this provision at all times that the aggregate amount of Credit Extensions outstanding exceeds Twenty-Five Million Dollars ($25,000,000.00). With respect to each request of a Credit Extension that, when made, would result in the aggregate amount of Credit Extensions outstanding exceeding Twenty-Five Million Dollars ($25,000,000.00), Borrower shall deliver to Bank evidence of Borrower’s compliance with this provision (after giving effect to such Credit Extension) as a condition precedent to such Credit Extension. If at any time the aggregate amount of Credit Extensions outstanding exceeds the amount permitted by this Section 2.2(b), then Borrower shall immediately pay to Bank in cash such excess.”

     “ (h) Float Charge. In connection with the computation of interest hereunder, during an Asset Based Period, Bank shall be entitled to charge Borrower a “float” charge in an amount equal to three (3) Business Days interest, at the interest rate applicable to the Credit Extensions, on all payments received

by Bank in the form of a check in respect of payments made by an Account Debtor. The float charge for each month shall be payable on the first day of the month.”

“ (a) timely receipt of a Notice of Borrowing;”

and inserting in lieu thereof the following:

“ (a) timely receipt of a Notice of Borrowing and, during an Asset Based Period, an executed Transaction Report;”

“ 5.12 Accounts Receivable. For any Eligible Account and Eligible Foreign Account in any Borrowing Base Certificate, all statements made and all unpaid balances appearing in all invoices, instruments and other documents evidencing such Eligible Accounts and Eligible Foreign Accounts are and shall be true and correct and all such invoices, instruments and other documents, and all of Borrower’s Books are genuine and in all respects what they purport to be. Whether or not an Event of Default has occurred and is continuing, Bank may notify any Account Debtor owing Borrower money of Bank’s security interest in such funds and verify the amount of such Eligible Account and Eligible Foreign Account. All sales and other transactions underlying or giving rise to each Eligible Account and Eligible Foreign Account shall comply in all material respects with all applicable laws and governmental rules and regulations. Borrower has no knowledge of any actual or imminent Insolvency Proceeding of any Account Debtor whose accounts are Eligible Accounts or Eligible Foreign Accounts in any Borrowing Base Certificate. To the best of Borrower’s knowledge, all signatures and endorsements on all documents, instruments, and agreements relating to all Eligible Accounts and Eligible Foreign Accounts are genuine, and all such documents, instruments and agreements are legally enforceable in accordance with their terms.”

“ (c) Within thirty (30) days after the last day of each month, deliver to Bank with the monthly financial statements, (i) a duly completed Borrowing Base Certificate signed by a Responsible Officer, and (ii) aged listings of accounts receivable and accounts payable (by invoice date).

     (d) During an Asset Based Period, unless a Streamline Period is then in effect, deliver to Bank, weekly, and upon each request for a Credit Extension, a Transaction Report.

     (e) Allow Bank to audit Borrower’s Collateral at Borrower’s expense. Such audits shall be conducted no more often than one (1) time per calendar year (or, during an Asset Based Period, two (2) times per calendar year) unless an Event of Default has occurred and is continuing. Borrower acknowledges that the first such audit will occur within sixty (60) days of the 2009 Effective Date.”

“ 6.7 Financial Covenants

     Borrower shall maintain at all times, to be tested as of the last day of each month, unless otherwise noted:

     (a) Adjusted Quick Ratio . An Adjusted Quick Ratio of at least (i) 0.90 to 1.0 through and including the month ending June 30, 2008, (ii) 1.0 to 1.0 as of the month ending July 31, 2008 through and including the month ending September 30, 2008, (iii) 1.10 to 1.00 as of October 31, 2008 through and including the month ending June 30, 2009, and (iv) 1.25 to 1.00 as of the month ending July 31, 2009 and thereafter.

     (b) EBITDA . As of the last day of each of Borrower’s fiscal quarters, commencing with the fiscal quarter ended October 31, 2007, Borrower shall have EBITDA for the six-month period ending on the last day of such quarter of at least (i) Five Million Dollars ($5,000,000.00) for the quarters ended October 31, 2007, January 31, 2008, April 30, 2008 and July 31, 2008, (ii) Twenty Million Dollars ($20,000,000.00) for the quarters ending October 31, 2008, January 31, 2009 and April 30, 2009, and (iii) Twenty-Five Million Dollars ($25,000,000.00) for the quarter ending on July 31, 2009 and as of the last day of each quarter thereafter.”

and inserting in lieu thereof the following:

“ 6.7 Financial Covenants

     Borrower shall maintain at all times, to be tested as of the last day of each month, unless otherwise noted:

     (a) Adjusted Quick Ratio .

     (i) Quarterly Adjusted Quick Ratio. An Adjusted Quick Ratio of at least (A) 1.10 to 1.00 as of the month ending April 30, 2009, (B) 1.15 to 1.00 as of the months ending July 31, 2009 and October 31, 2009, and (C) 1.25 to 1.00 as of the month ending January 31, 2010 and for the last month in each of Borrower’s quarters thereafter (it being understood that the last month in each of Borrower’s quarters is January, April, July and October).

     (ii) Intraquarterly Adjusted Quick Ratio . An Adjusted Quick Ratio of at least (A) 0.95 to 1.00 as of the months ending May 31, 2009 and June 30, 2009, and (B) 1.00 to 1.00 as of the month ending August 31, 2009 and for each of the first two months in each of Borrower’s quarters thereafter (it being understood that the first two months in each of Borrower’s quarters is February, March, May June, August September, November and December).

     (b) EBITDA . As of the last day of each of Borrower’s fiscal quarters, Borrower shall have EBITDA for the six-month period

ending on the last day of such quarter of at least (i) Fifteen Million Dollars ($15,000,000.00) for the quarter ending April 30, 2009, (ii) Seven Million Five Hundred Thousand Dollars ($7,500,000.00) for the quarter ending July 31, 2009, (iii) Fifteen Million Dollars ($15,000,000.00) for the quarter ending October 31, 2009, and (iv) Twenty Million Dollars ($20,000,000.00) for the quarter ending on January 31, 2010 and as of the last day of each quarter thereafter.”

“ 6.12 Accounts Receivable.

     (a) Schedules and Documents Relating to Accounts. During an Asset Based Period, unless a Streamline Period is then in effect, Borrower shall deliver to Bank transaction reports and schedules of collections, as provided in Section 6.2, on Bank’s standard forms; provided, however, that Borrower’s failure to execute and deliver the same shall not affect or limit Bank’s Lien and other rights in all of Borrower’s Accounts, nor shall Bank’s failure to advance or lend against a specific Account affect or limit Bank’s Lien and other rights therein. If reasonably requested by Bank during an Asset Based Period, unless a Streamline Period is then in effect, Borrower shall furnish Bank with copies (or, at Bank’s reasonable request, originals) of all contracts, orders, invoices, and other similar documents, and all shipping instructions, delivery receipts, bills of lading, and other evidence of delivery, for any goods the sale or disposition of which gave rise to such Accounts. In addition, during an Asset Based Period, unless a Streamline Period is then in effect, Borrower shall deliver to Bank, on its reasonable request, the originals of all instruments, chattel paper, security agreements, guarantees and other documents and property evidencing or securing any Accounts, in the same form as received, with all necessary endorsements, and copies of all credit memos.

     (b) Disputes. During an Asset Based Period, unless a Streamline Period is then in effect, Borrower shall promptly notify Bank of all disputes or claims relating to Accounts. Borrower may forgive (completely or partially), compromise, or settle any Account for less than payment in full, or agree to do any of the foregoing so long as (i) Borrower does so in good faith, in a commercially reasonable manner, in the ordinary course of business, in arm’s-length transactions, and reports the same to Bank in the regular reports provided to Bank; (ii) no Default or Event of Default has occurred and is continuing; and (iii) after taking into account all such discounts, settlements and forgiveness, the total outstanding Credit Extensions will not exceed the lesser of the Revolving Line or the Borrowing Base.

     (c) Collection of Accounts . During an Asset Based Period, unless a Streamline Period is then in effect, all payments on, and proceeds of, Accounts shall be deposited directly by the applicable Account Debtor into a lockbox account maintained by Borrower with Bank, and Borrower shall affirmatively direct each Account Debtor to make all payments to such lockbox. Whether or not an Event of Default has occurred and is continuing, Borrower shall hold all payments on, and proceeds of, Accounts in trust for Bank, and Borrower shall promptly deliver all such payments and proceeds to Bank in their original form, duly endorsed, to be applied to the Obligations pursuant to the terms of Section 9.5 hereof.

     (d) Returns . Provided no Event of Default has occurred and is continuing, during an Asset Based Period, unless a Streamline Period is then in effect, if any Account Debtor returns any Inventory to Borrower, Borrower shall promptly (i) determine the reason for such return, (ii) issue a credit memorandum to the Account Debtor in the appropriate amount to the extent consistent with Borrower’s customary practices or as otherwise appropriate in Borrower’s reasonable business judgment, and (iii) provide a copy of such credit memorandum to Bank, upon request from Bank. In the event any attempted return occurs after the occurrence and during the continuance of any Event of Default, Borrower shall hold the returned Inventory in trust for Bank, and immediately notify Bank of the return of the Inventory.

     (e) Veri