Exhibit 10.1

FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT

THIS FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT (this “First Amendment”), dated as of February 24, 2015 (the “Effective Date”), is made and entered into by and between SYCAMORE NETWORKS, INC. (the “Seller”) and PRINCETON TYNGSBORO COMMONS LLC (the “Buyer”).

R E C I T A L S

A. Seller and Buyer are parties to that certain Purchase and Sale Agreement dated as of October 10, 2014 (together, the “Purchase Agreement”) wherein the Buyer has agreed to purchase and Seller has agreed to sell that certain property consisting of 102.3 acres, more or less, located off Westford Road, Tyngsborough, Massachusetts as more particularly described in the Purchase Agreement, as well as the Supplemental Escrow Agreement dated October 14, 2014 regarding the Escrow Agent’s duties regarding deposits.

B. The time of the performance and delivery of the Deed for the transaction contemplated by the Purchase Agreement, as affected by that certain letter dated December 31, 2014 from the Buyer to the Seller, is presently scheduled to take place on February 27, 2015 (the “Current Closing Date”).

C. Seller and Buyer wish to extend the time of performance of the transaction contemplated by the Purchase Agreement.

AGREEMENT:

NOW, THEREFORE, in consideration of the premises, the sum of Ten Dollars and other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged and confessed, Seller and Buyer hereby agree as follows:

1. Extended Time of Performance.

The time of performance and delivery of the Deed for the transaction contemplated by the Purchase Agreement is hereby extended from the Current Closing Date to March 27, 2015.

2. Additional Deposit.

Within forty-eight (48) hours following the full execution of this First Amendment, the Buyer shall deliver an additional nonrefundable deposit of $100,000.00 to the Escrow Agent, which amount shall be added to the deposit presently held by the Escrow Agent and be subject to retention as set forth in Section 7 as amended by the new Closing Date set forth herein, Sections 17 and 18 of the Purchase Agreement, and the terms and conditions of Section 34 of the Purchase Agreement and the Supplemental Escrow Agreement. All deposits shall be credited towards the Purchase Price.

3. Ratification. Except as amended by this First Amendment, all other terms, conditions, covenants and provisions as appear in the Purchase Agreement and the Supplemental Escrow Agreement are hereby ratified and confirmed and shall remain unchanged.

IN WITNESS WHEREOF, the parties have caused this First Amendment to be duly executed under seal as of the date first written above.