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      OF
      FOLEY HOAG LLP


ATTORNEYS
      AT LAW]







June
                9, 2006




Terabeam,
      Inc.


2115
      O’Nel Drive


San
      Jose,
      CA 95131





Re:  Terabeam,
      Inc. 2004 Stock Plan




Ladies
      and Gentlemen:




We
      are
      familiar with the Registration Statement on Form S-8 (the “Registration
      Statement”) to be filed by Terabeam, Inc., a Delaware corporation (the
“Company”), with the Securities and Exchange Commission (the “Commission”) under
      the Securities Act of 1933, as amended (the “Securities Act”), relating to the
      offering by the Company of up to 2,000,000 shares (the “Shares”) of its common
      stock, par value $0.01 per share, issuable upon exercise of stock options and
      pursuant to other awards granted or to be granted pursuant to the Terabeam,
      Inc.
      2004 Stock Plan (the “Plan”).




In
      arriving at the opinion expressed below, we have examined and relied on the
      certificate of incorporation of the Company, as amended to date, the by-laws
      of
      the Company, as amended to date, the records of meetings and consents of the
      Board of Directors and stockholders of the Company provided to us by the
      Company, the Registration Statement and the Plan.




In
      addition, we have examined and relied on the originals or copies certified
      or
      otherwise identified to our satisfaction of all such corporate records of the
      Company and such other instruments and other certificates of public officials,
      officers and representatives of the Company and such other persons, and we
      have
      made such examination of law, as we have deemed appropriate as a basis for
      the
      opinion expressed below. This opinion is limited solely to the laws of the
      State
      of Delaware as applied by courts located in the State of Delaware. We express
      no
      opinion herein as to the securities or “blue sky” laws of any jurisdiction,
      including the State of Delaware.




We
      assume
      that all Shares to be issued upon exercise of options or pursuant to other
      awards granted or to be granted pursuant to the Plan will be issued in
      accordance with the terms of the Plan and that the purchase price of each Share,
      or the value of other lawful consideration received or to be received by the
      Company for the award of such Share, will be greater than or equal to the par
      value per share of such Share.




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            World Trade Center West / 155 Seaport Blvd. / Boston, MA 02210-2600 /
            TEL:
            617.832.1000 / FAX: 617.832.7000
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            Hoag  LLP  BOSTON  WASHINGTON,
            DC  www.foleyhoag.com
 
 Terabeam,
          Inc.
 June
          9,
          2006
 Page2


Based
      upon and subject to the foregoing, it is our opinion that the Shares, when
      issued and delivered upon the exercise of options or pursuant to other awards
      duly granted pursuant to the Plan and against the receipt of the purchase price
      or other lawful consideration therefor, will be validly issued, fully paid
      and
      nonassessable.




This
      opinion is being delivered solely for the benefit of the Company and such other
      persons as are entitled to rely upon it pursuant to applicable provisions of
      the
      Securities Act, and only while the Registration Statement is in effect. This
      opinion may not be used, quoted, relied upon or referred to for any other
      purpose nor may this opinion be used, quoted, relied upon or referred to by
      any
      other person, for any purpose, without our prior written consent.




Please
      note that we are opining only as to the matters expressly set forth herein,
      and
      no opinion should be inferred as to any other matters.




We
      hereby
      consent to the filing of this opinion as an exhibit to the Registration
      Statement in accordance with the requirements of Item 601(b)(5) of Regulation
      S-K under the Securities Act. In giving such consent, we do not admit that
      we
      are in the category of persons whose consent is required under Section 7 of
      the
      Securities Act or the rules and regulations of the Commission.




Very
                truly yours,FOLEY
                HOAG LLPBy:
            /s/
                John D. Hancocka
                Partner